6 PCs, all Level 17. Add: one Unicorn (Greater Steed), one Chipmunk Fighter companion (NPC), 6 "minions" (Ghouls, Ghasts, Ghosts), and an Echo Knight. PCs are as follows:
Dwarf Barbarian, Path of the Beast Tortle Monk, Drunken Master Vedalken Necromancer, Occultist Vedalken Blood Hunter, Order of the Mutant Goliath Fighter, Echo Knight Tabaxi Paladin, Oath of the Ancients
This is an incredibly balanced and powerful group of characters. Through general chitchat, I've learned of things they will "acquire" at Level 18, which is where they will be when they encounter the BBEG. I've been stressed about how to run *that* combat because I am a relatively new DM. This is my first campaign. I played in only three sessions as a player just prior. When I agreed to DM, I truly had no clue what I was doing, but I have come a very long way in 18 months since this campaign began. This campaign is homebrewed (I have heard-after the fact- that homebrew is not recommended for newbies, but it's water under the bridge and I'm too far in now to change anything...this story must go on! ). So far, the PCs have had nothing more than a scratch and I really want to dip my foot in the pool of PCs taking significant damage. While I still fear my BBEG combat will be weak and he'll go down in 2 or three rounds, maybe 4....I plan to present them a combat prior to that which will hopefully give them the sense they are not untouchable. The plan is to get their HP down far enough to be weakened to whatever degree when they face the BBEG. If nothing else they will be under pressure to protect the ever-squishy glass cannon Necromancer while trying to save their own skin.
So. In two weeks, they will encounter an army of Orcs (that, alone, will enrage the Dwarf). "Army" as in: 250 weapon-wielding brutal green guys.
The Barbarian was gifted a Horn of Valhalla recently and with the Rule of Cool, she will summon 180 Berserkers as the army descends upon the Party.
So, the question is: how to run this. I've been told that rather than have them roll for initiative, just ask them all what they will do for the first round, have them all roll, and indicate the results....then describe the returning attack of which ever Orc they're attacking, roll, and indicate the results. Then repeat for Round 2.
I've also been told to not have them try to go through all 250 Orcs. In movie scenes of combat, the camera focuses only on certain characters and their opponents....so handle it that way: combat is occurring in the background between Orcs and Berserkers; focus on the PC's and their opponent.
I can always create something that suddenly stops combat and all the remaining Orcs retreat. The Necro has an affinity for area effect spells, so I expect a great number of the Orcs to go down quick; calling for a retreat might not see the light of day.
And my biggest hurdle is getting the Orcs to have a solid chance at attacking out of the gate. One of the PC's has the ability to sense danger up to 180 feet, which gives the PCs tons of time to prepare for the onslaught and potentially screw my chances of a real combat. The best I've come up with is for them to encounter an Ophanim in a massive open field, which would cause blindness the longer they look at it (but something about it causes them to be entirely compelled to look at it). Even with total blindness, they would still sense oncoming danger, but maybe not exactly *how* eminent...aka: how much time they have before they're hit, and possibly only the general direction from which it is coming. The conflict with creating blindness is that the Barbarian would not get to use the Horn. Unless the blindness wears off and she summons the Berserkers in the middle of combat.
So, what do you advise for how to run the combat and how to have the Orcs show up and get a swing in before the PCs have a chance to block anything?
Give the orcs some siege weapons too. The fights are all at the BBEGs place right? What kind of home field advantage via traps and lair actions are there to help them out?
For context, I'm currently running a high level campaign with a lot of PCs. There are 8 total players, all 18th level. Most are optimized to a degree. They simply have the toolkit to deal with everything I throw at them. I had a fight that I was sure would be deadly, but our paladin multi class got a lucky crit and wound up dealing 1/4 of the monsters HP in his opening swing. Things like that happen all the time high level.
We can't give you perfect advice because there's a lot of homebrew happening here which you'd be the best person to know how to balance. That being said - is it just an evil humanoid BBEG with an army of other humanoids? Where are the monsters? If the party is at 17-18th level, will they be fighting any dragons during this climactic finale? Or other abominations?
The bits of advice so far for running a large wargame combat are good and I agree with them; think up a few big set piece moments to showcase how large the conflict is, but for the most part have the party focusing on individual groups of orcs. (Fair warning here, unless these are some busted orcs, a party consisting of everything you mentioned, past 17th level, will use the orcs to clean their shoes. It won't be a close fight).
Whatever plan you have for whittling them down, I'd suggest take that and add another beyond Deadly encounter on top. Players in basically endgame are nigh demi-gods, and will not go down easily. I'm not advocating killing them, because I doubt you will, and even then as the DM you'll have tools to internally balance things if needed. I just think this finale combat should be spicier than a dice rolling marathon against a horde of lookalike enemies.
So, the goal of the Orc fight is to give myself one last "dress rehersal" before the final combat. The Orcs are only one cluster of the BBGs army; there are clusters all over the Material Plane. Once they get through the Orc fight, then they will go after the BBG, but he is at the top of the mountain. He is a home-brewed version of a PC from the previous campaign. Dragonborn Cleric, LG turned CE, now a Warlock/Fighter, granted wings and change in physique, along with far more powerful spells and legendary Action/Spells/Resistances/Immunities, and has Lair Actions.
So, the goal of the Orc fight is to give myself one last "dress rehersal" before the final combat. The Orcs are only one cluster of the BBGs army; there are clusters all over the Material Plane. Once they get through the Orc fight, then they will go after the BBG, but he is at the top of the mountain. He is a home-brewed version of a PC from the previous campaign. Dragonborn Cleric, LG turned CE, now a Warlock/Fighter, granted wings and change in physique, along with far more powerful spells and legendary Action/Spells/Resistances/Immunities, and has Lair Actions.
This sounds all cool - I'd still recommend throwing in some monstrous enemies so that the party has more to attack than humanoids (even if they might have cool abilities).
Will there be any challenges in climbing the mountain? That could turn into a pseudo "combat" in its own right, if you have them required to make certain jumps, climbing sheer cliff faces, etc, all while enemies are attacking or even boulders or other effects are being hurled down the mountainside at them.
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I know what you're thinking: "In that flurry of blows, did he use all his ki points, or save one?" Well, are ya feeling lucky, punk?
Ok, first note: this will not work as a dress rehersal for a BBEG fight because mass combat vs solo-boss monster fights are completely different.
250 orcs vs 180 berserkers. Ideally the combat lasts ~4 rounds so it doesn't get too boring, and we need the party to feel important SO....
Each round ~60 orcs die and ~60 berserkers die while fighting each other in the background, if the party does nothing ~ 70 orcs survive after all berserkers are dead in at the end of the 3rd round of combat.
To simulate this I'd use: 15d10 for each group for round1, 15d8 for each group for round2, then 10d6 for losses for round3. If the party has a particularly good round you can move 2 dice from the berserkers to the orc, if they have a bad round you can move 2 dice from the orcs to the berserkers when determining losses.
Note: to add more drama, for round 1 roll the totals first and assign the greater losses to the berserkers. You can also pre-roll these to save time at the game table.
So that gives us 50-70 orcs for the party to kill.
Round1: 25 orcs start attacking the party Round2: add 15 more + Commando Round3: add 10 more + 2 unique beasts Round4: add 10 more + artillery
Let's create some minion rules to simplify things for generic orc grunts:
1) any orc that's hit by a PC dies. 2) any orc that's hit twice by a PC companion dies. 3) any orc that fails a saving throw against a spell that deals at least 30 damage dies, but survives if they succeed. 4) any orc targeted by a spell that deals at least 50 damage dies (save or fail).
Commando - this is some leader among the orcs who is CR ~10-14 and should be highly maneuverable (maybe mounted?), if/when the party kills him no more orcs join their fight.
Unique Beasts - these are like the trolls or elephants in LotR, something big and beefy that is different from the regular orcs in order to change things up, they should be CR 7-10 so they take a bit of effort to take down, but they can also be a hazard to the orcs themselves if the party manage to frightened them or confuse them or take control of them with some kind of check if they kill the riders of them. They should be Huge so they stand out and offer opportunities for "cool things" like jumping up onto them to attack archers riding on their backs.
Artillery - as a last-ditch attempt (or to cover their retreat) the orc start firing at the PCs using artillery from a long distance away, you can borrow catapult, or trebuchet stats from the DMG or invent your own flaming / explosive / poison shells to rain down onto the battlefield dealing AoE damage to orcs and party members alike.
So, what do you advise for how to run the combat and how to have the Orcs show up and get a swing in before the PCs have a chance to block anything?
That's what artillery are for! Give the orcs a bunch of siege weapons that they pelt at the PCs if the PCs try to snipe the orcs with superior range.
So, the goal of the Orc fight is to give myself one last "dress rehersal" before the final combat. The Orcs are only one cluster of the BBGs army; there are clusters all over the Material Plane. Once they get through the Orc fight, then they will go after the BBG, but he is at the top of the mountain. He is a home-brewed version of a PC from the previous campaign. Dragonborn Cleric, LG turned CE, now a Warlock/Fighter, granted wings and change in physique, along with far more powerful spells and legendary Action/Spells/Resistances/Immunities, and has Lair Actions.
If the goal of this fight is to actually put the fear of death into the PCs, then you're going to need to throw more at them. 250 orcs, even beefy orcs, versus a 17th-level party with 180 berserkers as backup plus other support probably isn't going to cut it
If this is the BBEG's home turf, then there should be traps set for the party. (That could screw with the danger sense, if the character is sensing danger everywhere, all around them at all times)
I'd also consider having the army of orcs be nothing more than a distraction or first wave, something to keep the party's attention in one place before something worse arrives in the valley -- summoned demons or whatever, depending on the plot, with the portal on the other side of the party from the orcs so they're caught in between
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Active characters:
Carric Aquissar, elven wannabe artist in his deconstructionist period (Archfey warlock) Lan Kidogo, mapach archaeologist and treasure hunter (Knowledge cleric) Mardan Ferres, elven private investigator obsessed with that one unsolved murder (Assassin rogue) Xhekhetiel, halfling survivor of a Betrayer Gods cult (Runechild sorcerer/fighter)
So, the goal of the Orc fight is to give myself one last "dress rehersal" before the final combat. The Orcs are only one cluster of the BBGs army; there are clusters all over the Material Plane. Once they get through the Orc fight, then they will go after the BBG, but he is at the top of the mountain. He is a home-brewed version of a PC from the previous campaign. Dragonborn Cleric, LG turned CE, now a Warlock/Fighter, granted wings and change in physique, along with far more powerful spells and legendary Action/Spells/Resistances/Immunities, and has Lair Actions.
OMG! Have you seen the Illusory Dragon Spell? Have your BBEG send an Illusory Dragon along with some sort of planar-bound creature(s) related to the BBEG's warlock patron to attack the PCs while they are climbing the mountain.
I didn't want to go into detail about the boss fight because it's not about that fight. The BBG isn't gonna just be sitting up in his lair by his lonesome self, not by any stretch of the imagination.
Note: a key point is that the Party has yet to deal with large numbers of enemies and I plan to give them that during the BBG fight, but I don't want to wait until then for large numbers because I need an in-action reference point of where I failed to run it well. There is entirely too much explaining as to why but I need the final fight to go very well.
Note: a key point is that the Party has yet to deal with large numbers of enemies and I plan to give them that during the BBG fight, but I don't want to wait until then for large numbers because I need an in-action reference point of where I failed to run it well. There is entirely too much explaining as to why but I need the final fight to go very well.
Large number doesn’t not necessarily mean harder or more lethal. A 17th level paladin can practically take on 250 orcs by themselves. Especially if they have good magic items
Note: a key point is that the Party has yet to deal with large numbers of enemies and I plan to give them that during the BBG fight, but I don't want to wait until then for large numbers because I need an in-action reference point of where I failed to run it well. There is entirely too much explaining as to why but I need the final fight to go very well.
Large number doesn’t not necessarily mean harder or more lethal. A 17th level paladin can practically take on 250 orcs by themselves. Especially if they have good magic items
Are you sure about that? With a one in five chance to hit, the orcs will do over 300 damage on their first turn.
Note: a key point is that the Party has yet to deal with large numbers of enemies and I plan to give them that during the BBG fight, but I don't want to wait until then for large numbers because I need an in-action reference point of where I failed to run it well. There is entirely too much explaining as to why but I need the final fight to go very well.
Large number doesn’t not necessarily mean harder or more lethal. A 17th level paladin can practically take on 250 orcs by themselves. Especially if they have good magic items
Are you sure about that? With a one in five chance to hit, the orcs will do over 300 damage on their first turn.
1) What makes you think they would have a 20 percent chance to hit? 2) How are they all getting attacks?
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Active characters:
Carric Aquissar, elven wannabe artist in his deconstructionist period (Archfey warlock) Lan Kidogo, mapach archaeologist and treasure hunter (Knowledge cleric) Mardan Ferres, elven private investigator obsessed with that one unsolved murder (Assassin rogue) Xhekhetiel, halfling survivor of a Betrayer Gods cult (Runechild sorcerer/fighter)
Note: a key point is that the Party has yet to deal with large numbers of enemies and I plan to give them that during the BBG fight, but I don't want to wait until then for large numbers because I need an in-action reference point of where I failed to run it well. There is entirely too much explaining as to why but I need the final fight to go very well.
Large number doesn’t not necessarily mean harder or more lethal. A 17th level paladin can practically take on 250 orcs by themselves. Especially if they have good magic items
Are you sure about that? With a one in five chance to hit, the orcs will do over 300 damage on their first turn.
1) What makes you think they would have a 20 percent chance to hit? 2) How are they all getting attacks?
They have a 20% chance to hit if the paladin has AC 21
They have javelin as a ranged attack with a 30 ft range.
Note: a key point is that the Party has yet to deal with large numbers of enemies and I plan to give them that during the BBG fight, but I don't want to wait until then for large numbers because I need an in-action reference point of where I failed to run it well. There is entirely too much explaining as to why but I need the final fight to go very well.
Large number doesn’t not necessarily mean harder or more lethal. A 17th level paladin can practically take on 250 orcs by themselves. Especially if they have good magic items
Are you sure about that? With a one in five chance to hit, the orcs will do over 300 damage on their first turn.
1) What makes you think they would have a 20 percent chance to hit? 2) How are they all getting attacks?
They have a 20% chance to hit if the paladin has AC 21
They have javelin as a ranged attack with a 30 ft range.
1. 21 AC is probably low at 17th level, even before you consider possibilities like the paladin having access to shield 2. A 13x13 box can contain a maximum of 169 orcs, and it would be strategic idiocy for even that many to be all packed into a tight space like that
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Active characters:
Carric Aquissar, elven wannabe artist in his deconstructionist period (Archfey warlock) Lan Kidogo, mapach archaeologist and treasure hunter (Knowledge cleric) Mardan Ferres, elven private investigator obsessed with that one unsolved murder (Assassin rogue) Xhekhetiel, halfling survivor of a Betrayer Gods cult (Runechild sorcerer/fighter)
Note: a key point is that the Party has yet to deal with large numbers of enemies and I plan to give them that during the BBG fight, but I don't want to wait until then for large numbers because I need an in-action reference point of where I failed to run it well. There is entirely too much explaining as to why but I need the final fight to go very well.
Large number doesn’t not necessarily mean harder or more lethal. A 17th level paladin can practically take on 250 orcs by themselves. Especially if they have good magic items
Are you sure about that? With a one in five chance to hit, the orcs will do over 300 damage on their first turn.
1) What makes you think they would have a 20 percent chance to hit? 2) How are they all getting attacks?
They have a 20% chance to hit if the paladin has AC 21
They have javelin as a ranged attack with a 30 ft range.
1. 21 AC is probably low at 17th level, even before you consider possibilities like the paladin having access to shield 2. A 13x13 box can contain a maximum of 169 orcs, and it would be strategic idiocy for even that many to be all packed into a tight space like that
I also wasn't factoring in crits. 1.5 This is only one turn and ignoring higher melee damage.
Note: a key point is that the Party has yet to deal with large numbers of enemies and I plan to give them that during the BBG fight, but I don't want to wait until then for large numbers because I need an in-action reference point of where I failed to run it well. There is entirely too much explaining as to why but I need the final fight to go very well.
Large number doesn’t not necessarily mean harder or more lethal. A 17th level paladin can practically take on 250 orcs by themselves. Especially if they have good magic items
Are you sure about that? With a one in five chance to hit, the orcs will do over 300 damage on their first turn.
That's largely irrelevant, nobody in their right mind is individually moving and rolling attacks for 250 creature each round.
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6 PCs, all Level 17. Add: one Unicorn (Greater Steed), one Chipmunk Fighter companion (NPC), 6 "minions" (Ghouls, Ghasts, Ghosts), and an Echo Knight. PCs are as follows:
Dwarf Barbarian, Path of the Beast
Tortle Monk, Drunken Master
Vedalken Necromancer, Occultist
Vedalken Blood Hunter, Order of the Mutant
Goliath Fighter, Echo Knight
Tabaxi Paladin, Oath of the Ancients
This is an incredibly balanced and powerful group of characters. Through general chitchat, I've learned of things they will "acquire" at Level 18, which is where they will be when they encounter the BBEG. I've been stressed about how to run *that* combat because I am a relatively new DM. This is my first campaign. I played in only three sessions as a player just prior. When I agreed to DM, I truly had no clue what I was doing, but I have come a very long way in 18 months since this campaign began. This campaign is homebrewed (I have heard-after the fact- that homebrew is not recommended for newbies, but it's water under the bridge and I'm too far in now to change anything...this story must go on! ). So far, the PCs have had nothing more than a scratch and I really want to dip my foot in the pool of PCs taking significant damage. While I still fear my BBEG combat will be weak and he'll go down in 2 or three rounds, maybe 4....I plan to present them a combat prior to that which will hopefully give them the sense they are not untouchable. The plan is to get their HP down far enough to be weakened to whatever degree when they face the BBEG. If nothing else they will be under pressure to protect the ever-squishy glass cannon Necromancer while trying to save their own skin.
So. In two weeks, they will encounter an army of Orcs (that, alone, will enrage the Dwarf). "Army" as in: 250 weapon-wielding brutal green guys.
The Barbarian was gifted a Horn of Valhalla recently and with the Rule of Cool, she will summon 180 Berserkers as the army descends upon the Party.
So, the question is: how to run this. I've been told that rather than have them roll for initiative, just ask them all what they will do for the first round, have them all roll, and indicate the results....then describe the returning attack of which ever Orc they're attacking, roll, and indicate the results. Then repeat for Round 2.
I've also been told to not have them try to go through all 250 Orcs. In movie scenes of combat, the camera focuses only on certain characters and their opponents....so handle it that way: combat is occurring in the background between Orcs and Berserkers; focus on the PC's and their opponent.
I can always create something that suddenly stops combat and all the remaining Orcs retreat. The Necro has an affinity for area effect spells, so I expect a great number of the Orcs to go down quick; calling for a retreat might not see the light of day.
And my biggest hurdle is getting the Orcs to have a solid chance at attacking out of the gate. One of the PC's has the ability to sense danger up to 180 feet, which gives the PCs tons of time to prepare for the onslaught and potentially screw my chances of a real combat. The best I've come up with is for them to encounter an Ophanim in a massive open field, which would cause blindness the longer they look at it (but something about it causes them to be entirely compelled to look at it). Even with total blindness, they would still sense oncoming danger, but maybe not exactly *how* eminent...aka: how much time they have before they're hit, and possibly only the general direction from which it is coming. The conflict with creating blindness is that the Barbarian would not get to use the Horn. Unless the blindness wears off and she summons the Berserkers in the middle of combat.
So, what do you advise for how to run the combat and how to have the Orcs show up and get a swing in before the PCs have a chance to block anything?
Look at the mob rules in the DMG. Also, it is important that the orcs would beat the berserkers without the pcs.
Give the orcs some siege weapons too. The fights are all at the BBEGs place right? What kind of home field advantage via traps and lair actions are there to help them out?
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For context, I'm currently running a high level campaign with a lot of PCs. There are 8 total players, all 18th level. Most are optimized to a degree. They simply have the toolkit to deal with everything I throw at them. I had a fight that I was sure would be deadly, but our paladin multi class got a lucky crit and wound up dealing 1/4 of the monsters HP in his opening swing. Things like that happen all the time high level.
We can't give you perfect advice because there's a lot of homebrew happening here which you'd be the best person to know how to balance. That being said - is it just an evil humanoid BBEG with an army of other humanoids? Where are the monsters? If the party is at 17-18th level, will they be fighting any dragons during this climactic finale? Or other abominations?
The bits of advice so far for running a large wargame combat are good and I agree with them; think up a few big set piece moments to showcase how large the conflict is, but for the most part have the party focusing on individual groups of orcs. (Fair warning here, unless these are some busted orcs, a party consisting of everything you mentioned, past 17th level, will use the orcs to clean their shoes. It won't be a close fight).
Whatever plan you have for whittling them down, I'd suggest take that and add another beyond Deadly encounter on top. Players in basically endgame are nigh demi-gods, and will not go down easily. I'm not advocating killing them, because I doubt you will, and even then as the DM you'll have tools to internally balance things if needed. I just think this finale combat should be spicier than a dice rolling marathon against a horde of lookalike enemies.
I know what you're thinking: "In that flurry of blows, did he use all his ki points, or save one?" Well, are ya feeling lucky, punk?
No, the combat will occur in a valley at the base of the mountain where the BBG is.j
So, the goal of the Orc fight is to give myself one last "dress rehersal" before the final combat. The Orcs are only one cluster of the BBGs army; there are clusters all over the Material Plane. Once they get through the Orc fight, then they will go after the BBG, but he is at the top of the mountain. He is a home-brewed version of a PC from the previous campaign. Dragonborn Cleric, LG turned CE, now a Warlock/Fighter, granted wings and change in physique, along with far more powerful spells and legendary Action/Spells/Resistances/Immunities, and has Lair Actions.
This sounds all cool - I'd still recommend throwing in some monstrous enemies so that the party has more to attack than humanoids (even if they might have cool abilities).
Will there be any challenges in climbing the mountain? That could turn into a pseudo "combat" in its own right, if you have them required to make certain jumps, climbing sheer cliff faces, etc, all while enemies are attacking or even boulders or other effects are being hurled down the mountainside at them.
I know what you're thinking: "In that flurry of blows, did he use all his ki points, or save one?" Well, are ya feeling lucky, punk?
Ok, first note: this will not work as a dress rehersal for a BBEG fight because mass combat vs solo-boss monster fights are completely different.
250 orcs vs 180 berserkers. Ideally the combat lasts ~4 rounds so it doesn't get too boring, and we need the party to feel important SO....
Each round ~60 orcs die and ~60 berserkers die while fighting each other in the background, if the party does nothing ~ 70 orcs survive after all berserkers are dead in at the end of the 3rd round of combat.
To simulate this I'd use: 15d10 for each group for round1, 15d8 for each group for round2, then 10d6 for losses for round3. If the party has a particularly good round you can move 2 dice from the berserkers to the orc, if they have a bad round you can move 2 dice from the orcs to the berserkers when determining losses.
Note: to add more drama, for round 1 roll the totals first and assign the greater losses to the berserkers. You can also pre-roll these to save time at the game table.
So that gives us 50-70 orcs for the party to kill.
Round1: 25 orcs start attacking the party
Round2: add 15 more + Commando
Round3: add 10 more + 2 unique beasts
Round4: add 10 more + artillery
Let's create some minion rules to simplify things for generic orc grunts:
1) any orc that's hit by a PC dies.
2) any orc that's hit twice by a PC companion dies.
3) any orc that fails a saving throw against a spell that deals at least 30 damage dies, but survives if they succeed.
4) any orc targeted by a spell that deals at least 50 damage dies (save or fail).
Commando - this is some leader among the orcs who is CR ~10-14 and should be highly maneuverable (maybe mounted?), if/when the party kills him no more orcs join their fight.
Unique Beasts - these are like the trolls or elephants in LotR, something big and beefy that is different from the regular orcs in order to change things up, they should be CR 7-10 so they take a bit of effort to take down, but they can also be a hazard to the orcs themselves if the party manage to frightened them or confuse them or take control of them with some kind of check if they kill the riders of them. They should be Huge so they stand out and offer opportunities for "cool things" like jumping up onto them to attack archers riding on their backs.
Artillery - as a last-ditch attempt (or to cover their retreat) the orc start firing at the PCs using artillery from a long distance away, you can borrow catapult, or trebuchet stats from the DMG or invent your own flaming / explosive / poison shells to rain down onto the battlefield dealing AoE damage to orcs and party members alike.
That's what artillery are for! Give the orcs a bunch of siege weapons that they pelt at the PCs if the PCs try to snipe the orcs with superior range.
If the goal of this fight is to actually put the fear of death into the PCs, then you're going to need to throw more at them. 250 orcs, even beefy orcs, versus a 17th-level party with 180 berserkers as backup plus other support probably isn't going to cut it
If this is the BBEG's home turf, then there should be traps set for the party. (That could screw with the danger sense, if the character is sensing danger everywhere, all around them at all times)
I'd also consider having the army of orcs be nothing more than a distraction or first wave, something to keep the party's attention in one place before something worse arrives in the valley -- summoned demons or whatever, depending on the plot, with the portal on the other side of the party from the orcs so they're caught in between
Active characters:
Carric Aquissar, elven wannabe artist in his deconstructionist period (Archfey warlock)
Lan Kidogo, mapach archaeologist and treasure hunter (Knowledge cleric)
Mardan Ferres, elven private investigator obsessed with that one unsolved murder (Assassin rogue)
Xhekhetiel, halfling survivor of a Betrayer Gods cult (Runechild sorcerer/fighter)
OMG! Have you seen the Illusory Dragon Spell? Have your BBEG send an Illusory Dragon along with some sort of planar-bound creature(s) related to the BBEG's warlock patron to attack the PCs while they are climbing the mountain.
I didn't want to go into detail about the boss fight because it's not about that fight. The BBG isn't gonna just be sitting up in his lair by his lonesome self, not by any stretch of the imagination.
Note: a key point is that the Party has yet to deal with large numbers of enemies and I plan to give them that during the BBG fight, but I don't want to wait until then for large numbers because I need an in-action reference point of where I failed to run it well. There is entirely too much explaining as to why but I need the final fight to go very well.
Large number doesn’t not necessarily mean harder or more lethal. A 17th level paladin can practically take on 250 orcs by themselves. Especially if they have good magic items
Blank
Are you sure about that? With a one in five chance to hit, the orcs will do over 300 damage on their first turn.
1) What makes you think they would have a 20 percent chance to hit?
2) How are they all getting attacks?
Active characters:
Carric Aquissar, elven wannabe artist in his deconstructionist period (Archfey warlock)
Lan Kidogo, mapach archaeologist and treasure hunter (Knowledge cleric)
Mardan Ferres, elven private investigator obsessed with that one unsolved murder (Assassin rogue)
Xhekhetiel, halfling survivor of a Betrayer Gods cult (Runechild sorcerer/fighter)
1. 21 AC is probably low at 17th level, even before you consider possibilities like the paladin having access to shield
2. A 13x13 box can contain a maximum of 169 orcs, and it would be strategic idiocy for even that many to be all packed into a tight space like that
Active characters:
Carric Aquissar, elven wannabe artist in his deconstructionist period (Archfey warlock)
Lan Kidogo, mapach archaeologist and treasure hunter (Knowledge cleric)
Mardan Ferres, elven private investigator obsessed with that one unsolved murder (Assassin rogue)
Xhekhetiel, halfling survivor of a Betrayer Gods cult (Runechild sorcerer/fighter)
Find a good friend that will help you manage the enemies.
"Sooner or later, your Players are going to smash your railroad into a sandbox."
-Vedexent
"real life is a super high CR."
-OboeLauren
"............anybody got any potatoes? We could drop a potato in each hole an' see which ones get viciously mauled by horrible monsters?"
-Ilyara Thundertale
That's largely irrelevant, nobody in their right mind is individually moving and rolling attacks for 250 creature each round.