So let me put the scenario out there since I'm not too sure if this is a normal occurrence. I started playing D&D again after many years (first experience was terrible so I wrote it off. Got invited to play with the group I now play with and it's been an extremely positive experience in my life) and it's really been a fun time and has helped me temporarily get away from some of the bad things going on in my life. A great friend of mine was listening to my experience with it and I casually offered to let her and her daughter play as a way to kind of keep her daughter involved in the conversation.
Fast forward to now and I'm in the process of building a campaign to teach them the game and to play with them. But both of them have no knowledge of D&D other than it existing. So I'm wondering if it would be okay (or if it's a common occurrence) to have a PC to help them out in their game. I'll try to keep the character as a follower so they're not being constantly led around by it and can make their own decisions as well.
So does anyone else have any experience doing this?
There are dozens of threads about this and a simple search can pull them up.
In short a DMPC is considered by the vast majority of experienced and skilled DMs to be a very bad idea. The idea is that you cannot have a character in the game that is *your* proxy or avatar. You can have NPCs that are well developed, interesting, and even powerful in your game, but they cannot be even for a moment the center of the game. That focus needs to be on the Player's characters. Think about Star Wars, in my head there are two NPCs that could be considered such NPCs, Obi-Wan Kenobi and Chewbacca. Neither is a PC, they can motivate the plot and even perform important tasks (like shutting down the tractor beam) but they don't make the PCs (Luke, Leia, and Han) unimportant. Ben just leaves to do a task that he can perform, and the PCs go to another area of the "Dungeon" to rescue the Princess. Chewie tags along to bring firepower and occasional humor to a scene (Get this walking carpet outta my way!). But in the end, the story rotates around those three PCs. The NPCs are important to meet with and interact with, but they are not the center!
I consider myself to have a lot of experience in this area because I spend around 80+% of my time running either solo games (one on one) or games with one DM and 2 players. As a result I create a large stable of NPCs for the Player Characters to interact with. My self check on whether an NPC is getting too big for it's britches is to ask a simple question: Does this plot point need a PC to solve it or is this plot point about expanding the NPCs role in the world? If the answer points to the NPC the idea is either rejiggered to fit the PC instead, scrapped, or happens off-screen because the Players are not here to see me play with myself. Thank you to Guy the Great GM for that phrasing.
There's nothing more frustrating than seeing the DM's PC, consciously or not, receive preferential treatment. It's a slippery slope, even with the best intentions. The DM knows the entirety of the campaign, so the character will end up being an NPC, or being the MVP, meaning you'll often end up playing with yourself (basically). It's much better to leave all of the agency and the moment to shine to the players.
An idea you could use are sidekicks, a concept introduce in Dragon of the Icepire Peak https://www.dndbeyond.com/sources/doip/sidekicks#Sidekicks . They are essentially NPCs tailored to help fill a spot in the team that's lacking. They have their limitations and limited abilities to ensure they leave the majority of the "fun" to the Players.
In general it is a bad idea, but you can consider the sidekick rules from the new Essential Kits.
Basically you need this character to not have any character arc, also not be a major damage output because that may take away the combat excitement for the new players. Usually a NPC with the party can be a quest/narrative giver, nothing more.
It’s a thing I did when I was like ten because I was the only person who was willing to GM but also I wanted to play “my” character. Then I grew up, I matured as a player and as a storyteller, and it stopped being fun.
I know that they wanted me to have a character with them as well, but judging by what everyone has said I might just have to basically have characters that accompany them so they have some battle backups instead of always having to be a duo
You could have an adventurer's league of sorts, where they can "hire" npcs to go along with them. It gives you a chance to try on many hats and personalities to see which they prefer as long-time companions. They could also see how some abilities and classes work, assuming you use a weaker version of a PC, or a sidekick. Since they can change from one mission to another, their actions shouldn't have as much of an impact to the main story line. Being friendly mercenaries teaching the players the ropes. (Think mentor figures that fade in the background).
You could have an adventurer's league of sorts, where they can "hire" npcs to go along with them. It gives you a chance to try on many hats and personalities to see which they prefer as long-time companions. They could also see how some abilities and classes work, assuming you use a weaker version of a PC, or a sidekick. Since they can change from one mission to another, their actions shouldn't have as much of an impact to the main story line. Being friendly mercenaries teaching the players the ropes. (Think mentor figures that fade in the background).
I like that idea. I'll probably try to do something like that with them. Regardless, I'll still get their opinion on what they would like for me to do, but if they're okay with this then I'll help them out. Either way, if I did play a PC in the campaign, they'd pretty much play like a side-kick because I wouldn't really allow the character to do much other than lead them in the right direction if they ever get stuck.
The game I have DM'd for a year now has had 3 PCs on average for most of the game - with my personal ideal being 4 PCs.
One thing I've done is building multiple NPCs that are A) important to the narrative of one SMALL PART of the overall story; B) give these NPCs chara sheets instead of simple stat blocks, so they feel "more" if they end up in battle; C) give them deep backstories; D) never let ANY SINGLE ONE EVER-EVER-EVER outshine, outspeak, or outdo a PC unless the PCs actually ask them to or without a REALLY TRULY important reason to; and E) NEVER let any one of these NPCs stick around for very long.
My rule of thumb: The NPC sticks around for just long enough that the PCs start to actually like or hate them, or otherwise get used to their usefulness, then tear them away for one reason or another. Then the PCs go awhile without ANY companion NPC, but eventually find another - or rediscover a previous one after it's been awhile. This prevents the "DM PC" thing to some extent, if you're careful, but also gives you the chance to interact with your PCs in-game in lots of different ways, wearing different hats, and giving your PCs reasons to invest in the world via if they find themselves fond of a "DM-N/PC" whose backstory they've learned and are following up after.
Being on both sides of thing (a DM who does this and having had a DM who does this), I have a few thoughts for different a few different areas. The major point, though, is that the NPC shouldn't be a major driving force, or, at the very least, no more than a normal NPC that isn't in the party.
GENERAL: Don't let the NPC outshine the party. If they have a backstory, it should be simply to flesh them out a tiny bit. It could also be integrated to the current arc, or a future one, but shouldn't take the center stage if so. Keep them in the background as much as possible. In my experience, keeping them around for too long detracts from this; have a rotating cast of varied NPCs.
COMBAT: The NPC should serve to cover an area that the players are lacking in, except in damage. The players should deal the vast majority of the encounter's damage -- or, at the very least, feel like they did. Distracting enemies at certain times or hobbling the enemies with spells such as Frostbite are ideal roles, as is healing. On the flip side, if it's an NPC the players care about, knocking them out is a GREAT way to ratchet up the tension.
EXPLORATION: The NPC should be able to provide lore and directions. Leave the actual challenges up to the party, with the NPC assisting if needed or asked to. For dungeons, the occasional interesting idea can be helpful. It should serve to guide the players towards a decision, not make it for them.
RP WITH OTHER NPCS: Keep the party's NPC out of this unless you have a specific reason not to (i.e. this is the NPC's turf, they're granting the party access to an area, etc). Major decisions and tipping points should belong to the players.
INTER-PARTY NPC: This is the best reason to have such an NPC. It lets you occasionally butt in to achieve a certain mood (humour, seriousness, etc). Additionally, if a player is doing some backstory revelations, having an NPC there can be amazing to hint at some elements of it they don't know, or some mystery that's linked to it. Changing up with NPC you use can let you interact with the party in different styles.
Tl;dr, the PCs should always be the stars of the show. The biggest danger is having your DMPC outshine them. Give the big players, the amazing moments, to the players. If your NPC gets a big play, it should be because they set one up for a PC, or took advantage of one the PCs set up for them. The NPC should be a tool to help the party. Nothing more.
If the DM doesn't have a big ego, then I think its good. I may be biased, since I use DMPC's, but I never actually do anything with them. They are apart of the main cast, but they come last whenever the party is doing something. I make them characters the party would want to talk to and interact with, so they go to them to talk, instead of me using them to take any spotlight. If the party is doing something, I will already be thinking about what my DMPC is doing. Usually they could ask something like, "Where's he at?", or "Is he doing something right now." and I can respond with something that makes the players wonder. My DMPC's are usually some form of evil, so if they went off to do something, it's assumed to be something they might want to know, but they don't need to look since it won't affect the grand plot.
Some of this might sound counteractive, but I think it all works out to letting the DM have a PC.
The distinction is between DMPC and NPC (below is my understanding ... other definitions may differ :)).
An NPC can be either a stat sheet from the monster manual or it can be a full character built using PC rules, or even just a brief character sketch on a napkin depending on what role the NPC will have in the module. An NPC based on a PC template can level up, perform all the actions of a PC, acquire magic items and do everything a PC can. They can join a party and assist as needed.
So, what is the difference between an NPC and a DMPC if an NPC can be based on a PC template? A DMPC is typically "their" character. A DM PC is the DMs personal PC in a campaign. The only time I have really seen this work well is in a campaign with experienced players that rotate the DM job. The DM has some limited input to what their character does but is otherwise hands off letting the other players run the character when they are running the game. However, the "attachment" some DMs feel towards their PC in the game can often cause issues in the game and between the players and the DM depending on what happens in the game. For example, if loot drops that is particularly beneficial to the DMPC, is that a coincidence or the DM favoring their character? If the DM puts in encounters where their DMPC is the best suited to dealing with them ... is that even fun for the other characters? Basically, it can work with a group of experienced players that know each other well but I would tend to not recommend using a DMPC otherwise.
On the other hand, NPCs using a PC template can become fun companions to a party. The DM roleplays them, they have their own mission and agenda (even if that is only getting paid) and can be a very useful addition to the party, particularly in covering weaknesses in small parties. The key difference is that an NPC is a part of the narration and has no personal connection to the DM.
The key difference is that an NPC is a part of the narration and has no personal connection to the DM.
This is the important part: A DM should feel no more sentiment for the NPC as they would hobgoblin #48, or Alysteriax the Blue Dragon or even The Mad Mage Halaster Blackcloak of Undermountain. They are all just puppets in the play you are crafting with the players. Don't ruin the fun by biasing the outcome because you gained affection for one of the puppets.
I have enough to handle running the game without running a PC myself too. I’ll never voluntarily run a PC as the DM because it’s too much extra work. Plus I’ve played in a game where the DM did that and it wasn’t fun.
Obv, if you have rotating dm, sure. If you're the DM for the entire game, tho, it's egregiously uncool. I've been using NPC's who may join the characters for a a few sessions or run into them, and if someone is at the house during a session wants to hop in, I can give them a short talk and then they can play that character. I play entirely original adventures but I don't even see this as a good idea in published adventures.
As others have said.. with rotating DMS it's fine.
Im DM for 7ppl and even when we had 3 I never had an active character of my own playing and I'll never do it. In the world I DM I'm the story teller, the world builder, the NPCs, the animals, the monsters. So there's no good reason to be playing a character when in have all that fun stuff to play already.
My players have asked a few NPCs to join them. I'm fine with that but they don't have an active role in what the players are doing. They've asked some very powerful NPCs why they don't just go kill an evil person and the explanation was that the players caused the trouble it's up to them to fix it.
So no. I wouldn't do it nor would in like the DM to have an active character in the campaign.
In a very similar situation, running D&D for my childhood friend and his two kids, I did have a "PC" in the game. It was completely fine. What you are talking about sounds more like an NPC, who takes a share of the loot and experience and levels up. I mean, NPCs are SUPPOSED to take a share of the XP and loot anyhow. I actually recommend this, because it allows your friend and her kid to play characters they are interested in, rather than feeling they need to play a certain class to make a well-rounded-out party.
To this end, my character (an npc I often use in undersized parties) is Childeric, the absent-minded life cleric. He wasn't very active, but if I needed to drop a hint and put an idea in my players' heads, then he would make some comment or another. Mostly, he didn't pay much attention and would just eat his prepared sandwiches. The kids loved him too. Just play the character more passively when a decision is to be made and it will be fine.
It really depends on how you do it. When I DMed for a short period of time in 4e, I used a DMPC, and my group loved her. That said, I was /very/ picky about what I did with her. She was a 4e lazy lord, a warlord class that used it's turn to enable other party members to do things, buff and heal. So she never did a point of damage to the enemy, she was helpful to the party, and enabled them to do more things. She never offered advice, and as a kind of crusty, bitter old hag told the PCs to figure things out for themselves. My party was mature enough to know that Verryn was there as a filler and didn't put me into awkward situations with her.
Sadly, the warlord is gone, so characters are expected to be a bit more active. if you choose to go the route of the DM PC, I would probably recommend a cleric. Buff the party, heal the party and perform the dodge action to help maintain your concentration. NEVER offer the party advice from the character, in fact, you might want to make the character unable to speak for some reason, perhaps a vow of silence or a vow to only speak celestial (which your PCs probably will not know). Take utility cantrips such as mending, guidance and light. Pick buff spells and heals and help them be the stars. They're not going to stop and think, "man, I hit that guy only because I had the extra d4 from bless!" they're going to care that they hit early and hit often. YOU may know and take some silent satisfaction from it, but they'll rightfully feel like the stars of the show.
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Any time an unfathomably powerful entity sweeps in and offers godlike rewards in return for just a few teensy favors, it’s a scam. Unless it’s me. I’d never lie to you, reader dearest.
In a very similar situation, running D&D for my childhood friend and his two kids, I did have a "PC" in the game. It was completely fine. What you are talking about sounds more like an NPC, who takes a share of the loot and experience and levels up. I mean, NPCs are SUPPOSED to take a share of the XP and loot anyhow. I actually recommend this, because it allows your friend and her kid to play characters they are interested in, rather than feeling they need to play a certain class to make a well-rounded-out party.
To this end, my character (an npc I often use in undersized parties) is Childeric, the absent-minded life cleric. He wasn't very active, but if I needed to drop a hint and put an idea in my players' heads, then he would make some comment or another. Mostly, he didn't pay much attention and would just eat his prepared sandwiches. The kids loved him too. Just play the character more passively when a decision is to be made and it will be fine.
This is pretty much what I've decided on doing. If I decide to give them a permanent NPC party member, it might just be a Warforged that functions on their orders. Or, like some people recommended, make it a cleric of some sort to help them out (provided one of them don't build one). Regardless, I want to try to make sure that the NPC can help them out in combat if need be, but nothing else. I do like the idea of making a character who's taken a vow of silence if going the cleric route.
If not that, I've been putting together characters in my head to kind of give them a bunch of NPCs that join/leave their party when the story requires them to.
As a DM, 've tried having basic NPCs in the group and the group inevitably asks them for advice... bypassing any of their own internal discussion. And they get accused of being garbage if they don't single handedly steamroll enemies.
And generally my old DM had PCs in the party who WERE significantly stronger to the point where it simply wasn't fun doing anything by comparison.
I give it a huge thumbs down.
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So let me put the scenario out there since I'm not too sure if this is a normal occurrence. I started playing D&D again after many years (first experience was terrible so I wrote it off. Got invited to play with the group I now play with and it's been an extremely positive experience in my life) and it's really been a fun time and has helped me temporarily get away from some of the bad things going on in my life. A great friend of mine was listening to my experience with it and I casually offered to let her and her daughter play as a way to kind of keep her daughter involved in the conversation.
Fast forward to now and I'm in the process of building a campaign to teach them the game and to play with them. But both of them have no knowledge of D&D other than it existing. So I'm wondering if it would be okay (or if it's a common occurrence) to have a PC to help them out in their game. I'll try to keep the character as a follower so they're not being constantly led around by it and can make their own decisions as well.
So does anyone else have any experience doing this?
There are dozens of threads about this and a simple search can pull them up.
In short a DMPC is considered by the vast majority of experienced and skilled DMs to be a very bad idea. The idea is that you cannot have a character in the game that is *your* proxy or avatar. You can have NPCs that are well developed, interesting, and even powerful in your game, but they cannot be even for a moment the center of the game. That focus needs to be on the Player's characters. Think about Star Wars, in my head there are two NPCs that could be considered such NPCs, Obi-Wan Kenobi and Chewbacca. Neither is a PC, they can motivate the plot and even perform important tasks (like shutting down the tractor beam) but they don't make the PCs (Luke, Leia, and Han) unimportant. Ben just leaves to do a task that he can perform, and the PCs go to another area of the "Dungeon" to rescue the Princess. Chewie tags along to bring firepower and occasional humor to a scene (Get this walking carpet outta my way!). But in the end, the story rotates around those three PCs. The NPCs are important to meet with and interact with, but they are not the center!
I consider myself to have a lot of experience in this area because I spend around 80+% of my time running either solo games (one on one) or games with one DM and 2 players. As a result I create a large stable of NPCs for the Player Characters to interact with. My self check on whether an NPC is getting too big for it's britches is to ask a simple question: Does this plot point need a PC to solve it or is this plot point about expanding the NPCs role in the world? If the answer points to the NPC the idea is either rejiggered to fit the PC instead, scrapped, or happens off-screen because the Players are not here to see me play with myself. Thank you to Guy the Great GM for that phrasing.
There's nothing more frustrating than seeing the DM's PC, consciously or not, receive preferential treatment. It's a slippery slope, even with the best intentions. The DM knows the entirety of the campaign, so the character will end up being an NPC, or being the MVP, meaning you'll often end up playing with yourself (basically). It's much better to leave all of the agency and the moment to shine to the players.
An idea you could use are sidekicks, a concept introduce in Dragon of the Icepire Peak https://www.dndbeyond.com/sources/doip/sidekicks#Sidekicks . They are essentially NPCs tailored to help fill a spot in the team that's lacking. They have their limitations and limited abilities to ensure they leave the majority of the "fun" to the Players.
In general it is a bad idea, but you can consider the sidekick rules from the new Essential Kits.
Basically you need this character to not have any character arc, also not be a major damage output because that may take away the combat excitement for the new players. Usually a NPC with the party can be a quest/narrative giver, nothing more.
It’s a thing I did when I was like ten because I was the only person who was willing to GM but also I wanted to play “my” character. Then I grew up, I matured as a player and as a storyteller, and it stopped being fun.
I know that they wanted me to have a character with them as well, but judging by what everyone has said I might just have to basically have characters that accompany them so they have some battle backups instead of always having to be a duo
You could have an adventurer's league of sorts, where they can "hire" npcs to go along with them. It gives you a chance to try on many hats and personalities to see which they prefer as long-time companions. They could also see how some abilities and classes work, assuming you use a weaker version of a PC, or a sidekick. Since they can change from one mission to another, their actions shouldn't have as much of an impact to the main story line. Being friendly mercenaries teaching the players the ropes. (Think mentor figures that fade in the background).
I like that idea. I'll probably try to do something like that with them. Regardless, I'll still get their opinion on what they would like for me to do, but if they're okay with this then I'll help them out. Either way, if I did play a PC in the campaign, they'd pretty much play like a side-kick because I wouldn't really allow the character to do much other than lead them in the right direction if they ever get stuck.
The game I have DM'd for a year now has had 3 PCs on average for most of the game - with my personal ideal being 4 PCs.
One thing I've done is building multiple NPCs that are A) important to the narrative of one SMALL PART of the overall story; B) give these NPCs chara sheets instead of simple stat blocks, so they feel "more" if they end up in battle; C) give them deep backstories; D) never let ANY SINGLE ONE EVER-EVER-EVER outshine, outspeak, or outdo a PC unless the PCs actually ask them to or without a REALLY TRULY important reason to; and E) NEVER let any one of these NPCs stick around for very long.
My rule of thumb: The NPC sticks around for just long enough that the PCs start to actually like or hate them, or otherwise get used to their usefulness, then tear them away for one reason or another. Then the PCs go awhile without ANY companion NPC, but eventually find another - or rediscover a previous one after it's been awhile. This prevents the "DM PC" thing to some extent, if you're careful, but also gives you the chance to interact with your PCs in-game in lots of different ways, wearing different hats, and giving your PCs reasons to invest in the world via if they find themselves fond of a "DM-N/PC" whose backstory they've learned and are following up after.
Being on both sides of thing (a DM who does this and having had a DM who does this), I have a few thoughts for different a few different areas. The major point, though, is that the NPC shouldn't be a major driving force, or, at the very least, no more than a normal NPC that isn't in the party.
GENERAL: Don't let the NPC outshine the party. If they have a backstory, it should be simply to flesh them out a tiny bit. It could also be integrated to the current arc, or a future one, but shouldn't take the center stage if so. Keep them in the background as much as possible. In my experience, keeping them around for too long detracts from this; have a rotating cast of varied NPCs.
COMBAT: The NPC should serve to cover an area that the players are lacking in, except in damage. The players should deal the vast majority of the encounter's damage -- or, at the very least, feel like they did. Distracting enemies at certain times or hobbling the enemies with spells such as Frostbite are ideal roles, as is healing. On the flip side, if it's an NPC the players care about, knocking them out is a GREAT way to ratchet up the tension.
EXPLORATION: The NPC should be able to provide lore and directions. Leave the actual challenges up to the party, with the NPC assisting if needed or asked to. For dungeons, the occasional interesting idea can be helpful. It should serve to guide the players towards a decision, not make it for them.
RP WITH OTHER NPCS: Keep the party's NPC out of this unless you have a specific reason not to (i.e. this is the NPC's turf, they're granting the party access to an area, etc). Major decisions and tipping points should belong to the players.
INTER-PARTY NPC: This is the best reason to have such an NPC. It lets you occasionally butt in to achieve a certain mood (humour, seriousness, etc). Additionally, if a player is doing some backstory revelations, having an NPC there can be amazing to hint at some elements of it they don't know, or some mystery that's linked to it. Changing up with NPC you use can let you interact with the party in different styles.
Tl;dr, the PCs should always be the stars of the show. The biggest danger is having your DMPC outshine them. Give the big players, the amazing moments, to the players. If your NPC gets a big play, it should be because they set one up for a PC, or took advantage of one the PCs set up for them. The NPC should be a tool to help the party. Nothing more.
If the DM doesn't have a big ego, then I think its good. I may be biased, since I use DMPC's, but I never actually do anything with them. They are apart of the main cast, but they come last whenever the party is doing something. I make them characters the party would want to talk to and interact with, so they go to them to talk, instead of me using them to take any spotlight. If the party is doing something, I will already be thinking about what my DMPC is doing. Usually they could ask something like, "Where's he at?", or "Is he doing something right now." and I can respond with something that makes the players wonder. My DMPC's are usually some form of evil, so if they went off to do something, it's assumed to be something they might want to know, but they don't need to look since it won't affect the grand plot.
Some of this might sound counteractive, but I think it all works out to letting the DM have a PC.
Also known as CrafterB and DankMemer.
Here, have some homebrew classes! Subclasses to? Why not races. Feats, feats as well. I have a lot of magic items. Lastly I got monsters, fun, fun times.
The distinction is between DMPC and NPC (below is my understanding ... other definitions may differ :)).
An NPC can be either a stat sheet from the monster manual or it can be a full character built using PC rules, or even just a brief character sketch on a napkin depending on what role the NPC will have in the module. An NPC based on a PC template can level up, perform all the actions of a PC, acquire magic items and do everything a PC can. They can join a party and assist as needed.
So, what is the difference between an NPC and a DMPC if an NPC can be based on a PC template? A DMPC is typically "their" character. A DM PC is the DMs personal PC in a campaign. The only time I have really seen this work well is in a campaign with experienced players that rotate the DM job. The DM has some limited input to what their character does but is otherwise hands off letting the other players run the character when they are running the game. However, the "attachment" some DMs feel towards their PC in the game can often cause issues in the game and between the players and the DM depending on what happens in the game. For example, if loot drops that is particularly beneficial to the DMPC, is that a coincidence or the DM favoring their character? If the DM puts in encounters where their DMPC is the best suited to dealing with them ... is that even fun for the other characters? Basically, it can work with a group of experienced players that know each other well but I would tend to not recommend using a DMPC otherwise.
On the other hand, NPCs using a PC template can become fun companions to a party. The DM roleplays them, they have their own mission and agenda (even if that is only getting paid) and can be a very useful addition to the party, particularly in covering weaknesses in small parties. The key difference is that an NPC is a part of the narration and has no personal connection to the DM.
This is the important part: A DM should feel no more sentiment for the NPC as they would hobgoblin #48, or Alysteriax the Blue Dragon or even The Mad Mage Halaster Blackcloak of Undermountain. They are all just puppets in the play you are crafting with the players. Don't ruin the fun by biasing the outcome because you gained affection for one of the puppets.
I have enough to handle running the game without running a PC myself too. I’ll never voluntarily run a PC as the DM because it’s too much extra work. Plus I’ve played in a game where the DM did that and it wasn’t fun.
Professional computer geek
Obv, if you have rotating dm, sure. If you're the DM for the entire game, tho, it's egregiously uncool. I've been using NPC's who may join the characters for a a few sessions or run into them, and if someone is at the house during a session wants to hop in, I can give them a short talk and then they can play that character. I play entirely original adventures but I don't even see this as a good idea in published adventures.
As others have said.. with rotating DMS it's fine.
Im DM for 7ppl and even when we had 3 I never had an active character of my own playing and I'll never do it. In the world I DM I'm the story teller, the world builder, the NPCs, the animals, the monsters. So there's no good reason to be playing a character when in have all that fun stuff to play already.
My players have asked a few NPCs to join them. I'm fine with that but they don't have an active role in what the players are doing. They've asked some very powerful NPCs why they don't just go kill an evil person and the explanation was that the players caused the trouble it's up to them to fix it.
So no. I wouldn't do it nor would in like the DM to have an active character in the campaign.
In a very similar situation, running D&D for my childhood friend and his two kids, I did have a "PC" in the game. It was completely fine. What you are talking about sounds more like an NPC, who takes a share of the loot and experience and levels up. I mean, NPCs are SUPPOSED to take a share of the XP and loot anyhow. I actually recommend this, because it allows your friend and her kid to play characters they are interested in, rather than feeling they need to play a certain class to make a well-rounded-out party.
To this end, my character (an npc I often use in undersized parties) is Childeric, the absent-minded life cleric. He wasn't very active, but if I needed to drop a hint and put an idea in my players' heads, then he would make some comment or another. Mostly, he didn't pay much attention and would just eat his prepared sandwiches. The kids loved him too. Just play the character more passively when a decision is to be made and it will be fine.
It really depends on how you do it. When I DMed for a short period of time in 4e, I used a DMPC, and my group loved her. That said, I was /very/ picky about what I did with her. She was a 4e lazy lord, a warlord class that used it's turn to enable other party members to do things, buff and heal. So she never did a point of damage to the enemy, she was helpful to the party, and enabled them to do more things. She never offered advice, and as a kind of crusty, bitter old hag told the PCs to figure things out for themselves. My party was mature enough to know that Verryn was there as a filler and didn't put me into awkward situations with her.
Sadly, the warlord is gone, so characters are expected to be a bit more active. if you choose to go the route of the DM PC, I would probably recommend a cleric. Buff the party, heal the party and perform the dodge action to help maintain your concentration. NEVER offer the party advice from the character, in fact, you might want to make the character unable to speak for some reason, perhaps a vow of silence or a vow to only speak celestial (which your PCs probably will not know). Take utility cantrips such as mending, guidance and light. Pick buff spells and heals and help them be the stars. They're not going to stop and think, "man, I hit that guy only because I had the extra d4 from bless!" they're going to care that they hit early and hit often. YOU may know and take some silent satisfaction from it, but they'll rightfully feel like the stars of the show.
Any time an unfathomably powerful entity sweeps in and offers godlike rewards in return for just a few teensy favors, it’s a scam. Unless it’s me. I’d never lie to you, reader dearest.
Tasha
This is pretty much what I've decided on doing. If I decide to give them a permanent NPC party member, it might just be a Warforged that functions on their orders. Or, like some people recommended, make it a cleric of some sort to help them out (provided one of them don't build one). Regardless, I want to try to make sure that the NPC can help them out in combat if need be, but nothing else. I do like the idea of making a character who's taken a vow of silence if going the cleric route.
If not that, I've been putting together characters in my head to kind of give them a bunch of NPCs that join/leave their party when the story requires them to.
As a DM, 've tried having basic NPCs in the group and the group inevitably asks them for advice... bypassing any of their own internal discussion. And they get accused of being garbage if they don't single handedly steamroll enemies.
And generally my old DM had PCs in the party who WERE significantly stronger to the point where it simply wasn't fun doing anything by comparison.
I give it a huge thumbs down.