The title basically says it all. The character is of a silly concept I thought up, which is part of a UA Loxodon (Elephant) character, partially because that a sneaky elephant amuses me to no end, but a somewhat tanky rogue is a strange character to play with. How would it be possible?
Either take the Moderately Armored feat, which grants proficiency in medium armor and shields, or take a multiclass level in a class that grants proficiency with a shieldfor multiclassing (Barbarian, Cleric, Druid, Fighter, Paladin, or Ranger).
Myself I would take like 3 levels of Fighter for the Medium Armor and Shields, Fighting style, Level 2 Action Surge, and Level 3 for Champion for the Crits on 19 and 20 which will help get more Crits on Surprise attack. You Also would gain access to all Martial Weapons, that allows for Whip use and having a reach weapon with finesse you can surprise attack at 10'ft.
Myself I would take like 3 levels of Fighter for the Medium Armor and Shields, Fighting style, Level 2 Action Surge, and Level 3 for Champion for the Crits on 19 and 20 which will help get more Crits on Surprise attack. You Also would gain access to all Martial Weapons, that allows for Whip use and having a reach weapon with finesse you can surprise attack at 10'ft.
Action surge, martial weapons, and most fighting styles don't mean much to a rogue because sneak attack does more damage and can only be done once per turn. As for whips, rogues can sneak attack with bows, crossbows, darts, or thrown daggers. All of which have better range and damage. The only real take away is armor proficiencies a feat could give, and improved critical (or a better fighter class) that will set him back 2 sneak attack improvements to get.
There's also the possibility of the DM allowing for you to use your downtime to learn it. It's something I do in my games when a player wants to learn a very specific ability. Shields, available weapons, tricks with spells, if a player wants to invest the time and resources into learning, why not let them.
There's also the possibility of the DM allowing for you to use your downtime to learn it. It's something I do in my games when a player wants to learn a very specific ability. Shields, available weapons, tricks with spells, if a player wants to invest the time and resources into learning, why not let them.
One answer to "why not let them?" could be "because why stop there? Why not allow Fighters to learn how to cast spells? Why not let them learn new skills? Why not let them learn how to sneak attack?" and so on. If Rogues can overcome a basic limitation of their class parameters simply with downtime activities, every class should be able to do so. And if every class should be able to do so, many groups might end up with, effectively, all Fighter/Paladin/Ranger/Bard/Wizard/Sorcerer/Warlock/Cleric/Rogue multiclassers. (Yes, I'm exaggerating to make a point, hehe.)
You have a point, it's very possible that you could take the munchkin route and let any character learn any thing. However, it's also necessary to use a little common sense and judgement on what is applicable and how difficult a goal would be to achieve. As well as understand that core mechanics of a class would not be something you'd be able to learn without cross classing.
Teaching a fighter how to cast spells would require a cross class due to the intense training and schooling that is required. Warlocks require a pact, innate ability indicates sorcerers. All of which would require cross classing.
Learning how to sneak up in the shadows and perform surgical strikes would require years to perfect. As would becoming proficient enough to beguile with music beyond an entertaining rendition on a lyre.
Picking up a shield and learning to protect yourself isn't quite as intricate of a skill to acquire. Could a person learn it over the course of a 3 day workshop...probably not. However using a month's down time on rigorous training might. In 3 months time, I could see that proficiency being permanent.
Sure, you could easily spend an asi on the feat, but if it's a simple weapon or shield I can make an exception. I like that some players will take the time to make it a story goal rather than a mechanical gain.
I meant more from a balance perspective. Part of what makes Sorcerers balanced is that they can't wear armor or use shields. Allowing them to do so without any penalty throws off the balance. Spending a Feat to do so has an opportunity cost. Same goes for Rogues and shields, although to a lesser degree.
If you're going to allow anybody to use a shield, that makes classes with shield proficiency slightly less attractive, and slightly underpowered. It might not be so noticeable, especially at first, but over time it can be. Also, there's the risk of the slippery slope; it can be hard to tell, beforehand, when you've crossed a line.
I meant more from a balance perspective. Part of what makes Sorcerers balanced is that they can't wear armor or use shields. Allowing them to do so without any penalty throws off the balance. Spending a Feat to do so has an opportunity cost. Same goes for Rogues and shields, although to a lesser degree.
If you're going to allow anybody to use a shield, that makes classes with shield proficiency slightly less attractive, and slightly underpowered. It might not be so noticeable, especially at first, but over time it can be. Also, there's the risk of the slippery slope; it can be hard to tell, beforehand, when you've crossed a line.
Again, I agree that it could lead into a spiraling vortex of oops.
If you can spend a feat to learn how to use a shield, how does that keep the balance any more/less? Technically by only learning how to use the shield you're getting half a feat, since you don't gain proficiency in the armors associated to that feat. That could be considered aiding in unbalancing the game a touch.
A fighter gets the shield as a proficiency at creation, a rogue or sorcerer goes variant human and picks medium armor proficiency at creation, it's getting the proficiency at the same time. How does that add to the imbalance? Especially since, in the case of a spell caster, they'd have to take another feat to use it effectively while casting, and they generally have better options. This would trivialize the uniqueness of a fighter with a shield in the party since both have it. Is that underpowering or unbalancing the game?
The game is fairly balanced, given that players can do just about anything. For the pedantic side of this argument: "You can spend time between adventures learning a new language or training with a set of tools. Your DM might allow additional training options." This indicates that the DM could allow for something like shield/weapon training.
As with anything in D&D, when it comes to bending/breaking RAW, it's gotta be done with forethought into how it will manifest issues later in the game. A +2 AC can be a big boon early game however, later on, that +2 will begin to mean less and less.
Xanathar's Guide gives you optional rules for learning new proficiencies during downtime. The short version is that it takes a number of workweeks equal to (10 - INT mod), and costs 25 gold per workweek. Also you'd have to find an instructor.
There are also tables for determining if anything goes wrong during your training, should the GM decide to go that route. >:3
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A bit more of a focus on the important part of that quote. Options, such as different ways to learn those languages or tools. It could also be used in the form of: Options, such as different things to learn. In the way of weapon, armor, skills, saving throws, or whatever else the DM feels generous(crazy) enough to allow.
While I understand your reluctance to allow this particular course of action, I am only intent on showing that it is a possible course of action. I do not, in any way, want to imply that you are doing something wrong in your games.
You've got a few options at face value for multiclassing to get Shield proficiency: Barbarian, Cleric, Druid, Fighter, Paladin, and Ranger. There is, however, another option that isn't as obvious - the Hexblade Warlock. I'll go over why I believe Hexblade is the most potent multiclass to get your desired shield proficiency, while also going over your other options.
Barbarian and Paladin are most likely not viable options for your multiclass. Both require 13 STR in order to multiclass into, which - as a Rogue - is almost certainly a dump stat for you.
Cleric could be viable - you only need 13 WIS to multiclass into it, which isn't too bad - and you also get your divine domain at level 1. Depending on which domain you take, You could get some decent small buffs (such as skill proficiencies, imposing disadvantage on an attack against you once per long rest, etc), and Cleric also gives you access to a couple of cool spells such as cure wounds. Note, however, that the big thing for the domains - Channel divinity - comes online at Cleric level 2, which will cost you an ASI if you want to get it. Also, a Cleric multiclass will not give you martial weapons - only shields and medium armor.
Druid also requires 13 WIS, so if you can multiclass into here, you can go either Cleric or Ranger as well. Druid seems pretty decent on paper, but remember that Druids will not wear armor or shields made of metal. That studded leather armor you're probably using? Can't use it if you multiclass druid. You also don't get your Druid Circle subclass until level 2 (which, like with the Cleric's channel divinity, will cost you an ASI), and a Druid multiclass also does not include martial weapon proficiency
Fighter is never a terrible option for a multiclass, but to get the most out of it (action surge is the main reason people go for it), you again need to go for level 2 which will again cost you an ASI. Action surge is also pretty underwhelming for a Rogue, as you can only get sneak attack once per turn, so action surge will not give you a second chance to sneak attack. Fighter also doesn't get its subclass until level 3 - but if you're picking fighter for action surge, you may as well get that subclass anyway.
Ranger... I honestly don't know too much about rangers, so I'm looking this up as I type. Multiclassing here does require WIS 13, like Druid and Cleric, as well as Dex 13 (which obviously shouldn't be a problem for a Rogue). It gives you your shield proficiency, as well as medium armor and martial weapons, and proficiency in a skill from the ranger's list. Level 1 Ranger also gives you your preferred enemy - decent for thematic campaigns like curse of Strahd - and favored terrain, which can be useful if your party doesn't already have a ranger. Having just now looked at what the ranger has to offer, it's honestly not a terrible choice in certain situations. Just note that you don't get Ranger spellcasting until level 2 or Ranger archtype until level 3, either of which will cost you an ASI.
And now we get to the one I recommend. One of the easiest and most rewarding ways to get shield proficiency, in my opinion, is taking a single level in Hexblade Warlock. Do note, however, that a Warlock multiclass requires 13 CHA, which may or may not be an issue for you. 1 level of Hexblade gives you:
- Proficiency in medium armor and shields, as well as all martial weapons (Which for a Rogue will really only help for getting proficiency with certain ranged weapons, like Longbow for non-Wood Elves or Light / Heavy Crossbows).
- A single spell slot and two spells to choose from, along with 2 cantrips, which is pretty cool for any non-AT rogue to get access to magic.
-The Hexblade's curse, which lets you mark a target once per short rest. The target gets crit on a 19 as well as the usual 20. It also takes additional damage equal to your proficiency bonus every time you hit it with any attack, and if it dies you regain hp equal to your warlock level + CHA modifier.
All of this at the low, low cost of not getting the Rogue's level 20 class ability, Stroke of Luck. A single-level dip into Warlock will give you all of the above and not cost you any ASI's. If you do decide to proceed further, you get eldritich invocations (like Devil's Sight) at level 2, and level 2 spells (Such as invisibility) at level 3., as well as a pact (Chain, Tome, or Blade). Personally, I like the Pact of the Tome, as it - along with the eldritch invocation, Book of Dark secrets - gives you access to certain spells you would otherwise not be able to get... such as find familiar.
So yeah. I recommend Hexblade Warlock for a Rogue multiclass to gain shield proficiency. Having played a Rogue that mutliclassed to become Assassin 12 / Hexblade 3, I can tell you right now that it's quite a sight to see your Rogue tanking with a shield for your party. It really throws your DM for a loop. Rogue's are already pretty durable with Uncanny Dodge and evasion, so throw A shield and medium armor on top of that... Yeah. A good weapon to potentially aim for could be a Nine Live's Stealer (Which forces your target to make a DC 15 CON save or die if it's crit while under 100 HP - remember that the hexblade's curse lets you crit on a 19).
One can action surge a held action to go off on another creature's turn. Thus getting an additional sneak attack. An excellent use of a short rest ability and a reaction.
Improved critical is very potent on a rogue where your main damage comes from dice. Shields are another big draw- as I'm sure many rogues can attest. The Archery, armored, and duelling fighting styles can all be very helpful depending on your play style as well.
Note that the normal Warlock does not grant shields. Only the Hexblade gets it.
For most people the reason for a Rogue to get Warlock is for Eldritch Blast. One level of Warlock grants you Eldritch Blast. If you are level 1 Warlock, 4 Rogue, you still get 2 EB rays, which grants you two chances for a hit. And being a ranged attack, it counts for Sneak Attack. You even get more attacks at higher levels. This is more important than the other Warlock abilities, but most importantly it stacks very well with the Hex Curse.
Once you Hex someone, ALL of those EB's get the increased crit range and the proficiency bonus to damage. A 16th level Rogue/1 Hexblade Warlock gets 4 EB, which against a Cursed target each do 1d10+6, for a max 4d10+24. One of them can do an extra 8d6 Sneak Attack damage, and you have 8/20 chances of critting.
If you hit on all of them, critting on the first hit which is also a Sneak Attack, then your total damage for using a CANTRIP and not a single consumable resource is 24+16d6 sneak attack + 7d10.
You cannot use Sneak Attack on spell attacks, the feature specifies weapon attacks only. Taking Warlock for EB does nothing useful for a character built around Sneak Attack.
Sneak Attack
Beginning at 1st level, you know how to strike subtly and exploit a foe’s distraction. Once per turn, you can deal an extra 1d6 damage to one creature you hit with an attack if you have advantage on the attack roll. The attack must use a finesse or a ranged weapon.
You don’t need advantage on the attack roll if another enemy of the target is within 5 feet of it, that enemy isn’t incapacitated, and you don’t have disadvantage on the attack roll.
The amount of the extra damage increases as you gain levels in this class, as shown in the Sneak Attack column of the Rogue table.
One can action surge a held action to go off on another creature's turn. Thus getting an additional sneak attack. An excellent use of a short rest ability and a reaction.
Improved critical is very potent on a rogue where your main damage comes from dice. Shields are another big draw- as I'm sure many rogues can attest. The Archery, armored, and duelling fighting styles can all be very helpful depending on your play style as well.
Sneak Attack happens per turn, not per round. Any Reaction Attack made by a Rogue can already use sneak attack as long as it is made on another creature’s turn.
I'd argue training to develop a shield proficiency isn't too much of a game-breaker, balance-wise. The argument of "if you give them an inch, they'll take a mile" doesn't really apply here, as the DM is god, so saying "yeah, you can train yourself to learn to use a shield, no you can't train yourself to cast wish" is just... responsible use of rule zero. If you want to create a measurable cost, then develop a side-quest to find a trainer, get a special shield, DO some kind of training exercise that challenges the player in their downtime.
That said, you could also talk to your DM about modifying the class to allow a little more flexibility. For instance, maybe you get shield proficiency, but you give up an expertise option, or 1d6 of sneak attack damage to reflect time spent away from roguish enterprise and focused on more martial endeavors. If you do this, make sure you give up something valuable in exchange for it. Saying "oh, I give up dagger proficiency for shield proficiency" is no good. You're giving up something you won't miss in exchange for a useful class feature. In general, if you feel like you're getting screwed on the deal, it's probably a fair trade.
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The title basically says it all. The character is of a silly concept I thought up, which is part of a UA Loxodon (Elephant) character, partially because that a sneaky elephant amuses me to no end, but a somewhat tanky rogue is a strange character to play with. How would it be possible?
Medium armor proficiency feat
”moderately armored”
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D&D Beyond FoundersEither take the Moderately Armored feat, which grants proficiency in medium armor and shields, or take a multiclass level in a class that grants proficiency with a shield for multiclassing (Barbarian, Cleric, Druid, Fighter, Paladin, or Ranger).
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Myself I would take like 3 levels of Fighter for the Medium Armor and Shields, Fighting style, Level 2 Action Surge, and Level 3 for Champion for the Crits on 19 and 20 which will help get more Crits on Surprise attack. You Also would gain access to all Martial Weapons, that allows for Whip use and having a reach weapon with finesse you can surprise attack at 10'ft.
Action surge, martial weapons, and most fighting styles don't mean much to a rogue because sneak attack does more damage and can only be done once per turn. As for whips, rogues can sneak attack with bows, crossbows, darts, or thrown daggers. All of which have better range and damage. The only real take away is armor proficiencies a feat could give, and improved critical (or a better fighter class) that will set him back 2 sneak attack improvements to get.
There's also the possibility of the DM allowing for you to use your downtime to learn it. It's something I do in my games when a player wants to learn a very specific ability. Shields, available weapons, tricks with spells, if a player wants to invest the time and resources into learning, why not let them.
One answer to "why not let them?" could be "because why stop there? Why not allow Fighters to learn how to cast spells? Why not let them learn new skills? Why not let them learn how to sneak attack?" and so on. If Rogues can overcome a basic limitation of their class parameters simply with downtime activities, every class should be able to do so. And if every class should be able to do so, many groups might end up with, effectively, all Fighter/Paladin/Ranger/Bard/Wizard/Sorcerer/Warlock/Cleric/Rogue multiclassers. (Yes, I'm exaggerating to make a point, hehe.)
You have a point, it's very possible that you could take the munchkin route and let any character learn any thing. However, it's also necessary to use a little common sense and judgement on what is applicable and how difficult a goal would be to achieve. As well as understand that core mechanics of a class would not be something you'd be able to learn without cross classing.
Teaching a fighter how to cast spells would require a cross class due to the intense training and schooling that is required. Warlocks require a pact, innate ability indicates sorcerers. All of which would require cross classing.
Learning how to sneak up in the shadows and perform surgical strikes would require years to perfect. As would becoming proficient enough to beguile with music beyond an entertaining rendition on a lyre.
Picking up a shield and learning to protect yourself isn't quite as intricate of a skill to acquire. Could a person learn it over the course of a 3 day workshop...probably not. However using a month's down time on rigorous training might. In 3 months time, I could see that proficiency being permanent.
Sure, you could easily spend an asi on the feat, but if it's a simple weapon or shield I can make an exception. I like that some players will take the time to make it a story goal rather than a mechanical gain.
I meant more from a balance perspective. Part of what makes Sorcerers balanced is that they can't wear armor or use shields. Allowing them to do so without any penalty throws off the balance. Spending a Feat to do so has an opportunity cost. Same goes for Rogues and shields, although to a lesser degree.
If you're going to allow anybody to use a shield, that makes classes with shield proficiency slightly less attractive, and slightly underpowered. It might not be so noticeable, especially at first, but over time it can be. Also, there's the risk of the slippery slope; it can be hard to tell, beforehand, when you've crossed a line.
Again, I agree that it could lead into a spiraling vortex of oops.
If you can spend a feat to learn how to use a shield, how does that keep the balance any more/less? Technically by only learning how to use the shield you're getting half a feat, since you don't gain proficiency in the armors associated to that feat. That could be considered aiding in unbalancing the game a touch.
A fighter gets the shield as a proficiency at creation, a rogue or sorcerer goes variant human and picks medium armor proficiency at creation, it's getting the proficiency at the same time. How does that add to the imbalance? Especially since, in the case of a spell caster, they'd have to take another feat to use it effectively while casting, and they generally have better options. This would trivialize the uniqueness of a fighter with a shield in the party since both have it. Is that underpowering or unbalancing the game?
The game is fairly balanced, given that players can do just about anything. For the pedantic side of this argument: "You can spend time between adventures learning a new language or training with a set of tools. Your DM might allow additional training options." This indicates that the DM could allow for something like shield/weapon training.
As with anything in D&D, when it comes to bending/breaking RAW, it's gotta be done with forethought into how it will manifest issues later in the game. A +2 AC can be a big boon early game however, later on, that +2 will begin to mean less and less.
Xanathar's Guide gives you optional rules for learning new proficiencies during downtime. The short version is that it takes a number of workweeks equal to (10 - INT mod), and costs 25 gold per workweek. Also you'd have to find an instructor.
There are also tables for determining if anything goes wrong during your training, should the GM decide to go that route. >:3
"We're the perfect combination of expendable and unkillable!"
That's for languages and tool proficiencies, though. Not for weapon, armor, saving throw, or skill proficiencies. =)
Your DM might allow additional training options.
A bit more of a focus on the important part of that quote. Options, such as different ways to learn those languages or tools. It could also be used in the form of: Options, such as different things to learn. In the way of weapon, armor, skills, saving throws, or whatever else the DM feels generous(crazy) enough to allow.
While I understand your reluctance to allow this particular course of action, I am only intent on showing that it is a possible course of action. I do not, in any way, want to imply that you are doing something wrong in your games.
For sure, and I never thought you, or anyone, were saying that. :)
I'm a natural troubleshooter, so I tend to look for potential problems out of instinct. Doesn't mean those problems have no solution. 👍
You've got a few options at face value for multiclassing to get Shield proficiency: Barbarian, Cleric, Druid, Fighter, Paladin, and Ranger. There is, however, another option that isn't as obvious - the Hexblade Warlock. I'll go over why I believe Hexblade is the most potent multiclass to get your desired shield proficiency, while also going over your other options.
Barbarian and Paladin are most likely not viable options for your multiclass. Both require 13 STR in order to multiclass into, which - as a Rogue - is almost certainly a dump stat for you.
Cleric could be viable - you only need 13 WIS to multiclass into it, which isn't too bad - and you also get your divine domain at level 1. Depending on which domain you take, You could get some decent small buffs (such as skill proficiencies, imposing disadvantage on an attack against you once per long rest, etc), and Cleric also gives you access to a couple of cool spells such as cure wounds. Note, however, that the big thing for the domains - Channel divinity - comes online at Cleric level 2, which will cost you an ASI if you want to get it. Also, a Cleric multiclass will not give you martial weapons - only shields and medium armor.
Druid also requires 13 WIS, so if you can multiclass into here, you can go either Cleric or Ranger as well. Druid seems pretty decent on paper, but remember that Druids will not wear armor or shields made of metal. That studded leather armor you're probably using? Can't use it if you multiclass druid. You also don't get your Druid Circle subclass until level 2 (which, like with the Cleric's channel divinity, will cost you an ASI), and a Druid multiclass also does not include martial weapon proficiency
Fighter is never a terrible option for a multiclass, but to get the most out of it (action surge is the main reason people go for it), you again need to go for level 2 which will again cost you an ASI. Action surge is also pretty underwhelming for a Rogue, as you can only get sneak attack once per turn, so action surge will not give you a second chance to sneak attack. Fighter also doesn't get its subclass until level 3 - but if you're picking fighter for action surge, you may as well get that subclass anyway.
Ranger... I honestly don't know too much about rangers, so I'm looking this up as I type. Multiclassing here does require WIS 13, like Druid and Cleric, as well as Dex 13 (which obviously shouldn't be a problem for a Rogue). It gives you your shield proficiency, as well as medium armor and martial weapons, and proficiency in a skill from the ranger's list. Level 1 Ranger also gives you your preferred enemy - decent for thematic campaigns like curse of Strahd - and favored terrain, which can be useful if your party doesn't already have a ranger. Having just now looked at what the ranger has to offer, it's honestly not a terrible choice in certain situations. Just note that you don't get Ranger spellcasting until level 2 or Ranger archtype until level 3, either of which will cost you an ASI.
And now we get to the one I recommend. One of the easiest and most rewarding ways to get shield proficiency, in my opinion, is taking a single level in Hexblade Warlock. Do note, however, that a Warlock multiclass requires 13 CHA, which may or may not be an issue for you. 1 level of Hexblade gives you:
- Proficiency in medium armor and shields, as well as all martial weapons (Which for a Rogue will really only help for getting proficiency with certain ranged weapons, like Longbow for non-Wood Elves or Light / Heavy Crossbows).
- A single spell slot and two spells to choose from, along with 2 cantrips, which is pretty cool for any non-AT rogue to get access to magic.
-The Hexblade's curse, which lets you mark a target once per short rest. The target gets crit on a 19 as well as the usual 20. It also takes additional damage equal to your proficiency bonus every time you hit it with any attack, and if it dies you regain hp equal to your warlock level + CHA modifier.
All of this at the low, low cost of not getting the Rogue's level 20 class ability, Stroke of Luck. A single-level dip into Warlock will give you all of the above and not cost you any ASI's. If you do decide to proceed further, you get eldritich invocations (like Devil's Sight) at level 2, and level 2 spells (Such as invisibility) at level 3., as well as a pact (Chain, Tome, or Blade). Personally, I like the Pact of the Tome, as it - along with the eldritch invocation, Book of Dark secrets - gives you access to certain spells you would otherwise not be able to get... such as find familiar.
So yeah. I recommend Hexblade Warlock for a Rogue multiclass to gain shield proficiency. Having played a Rogue that mutliclassed to become Assassin 12 / Hexblade 3, I can tell you right now that it's quite a sight to see your Rogue tanking with a shield for your party. It really throws your DM for a loop. Rogue's are already pretty durable with Uncanny Dodge and evasion, so throw A shield and medium armor on top of that... Yeah. A good weapon to potentially aim for could be a Nine Live's Stealer (Which forces your target to make a DC 15 CON save or die if it's crit while under 100 HP - remember that the hexblade's curse lets you crit on a 19).
One can action surge a held action to go off on another creature's turn. Thus getting an additional sneak attack. An excellent use of a short rest ability and a reaction.
Improved critical is very potent on a rogue where your main damage comes from dice. Shields are another big draw- as I'm sure many rogues can attest. The Archery, armored, and duelling fighting styles can all be very helpful depending on your play style as well.
Note that the normal Warlock does not grant shields. Only the Hexblade gets it.
For most people the reason for a Rogue to get Warlock is for Eldritch Blast. One level of Warlock grants you Eldritch Blast. If you are level 1 Warlock, 4 Rogue, you still get 2 EB rays, which grants you two chances for a hit. And being a ranged attack, it counts for Sneak Attack. You even get more attacks at higher levels. This is more important than the other Warlock abilities, but most importantly it stacks very well with the Hex Curse.
Once you Hex someone, ALL of those EB's get the increased crit range and the proficiency bonus to damage. A 16th level Rogue/1 Hexblade Warlock gets 4 EB, which against a Cursed target each do 1d10+6, for a max 4d10+24. One of them can do an extra 8d6 Sneak Attack damage, and you have 8/20 chances of critting.
If you hit on all of them, critting on the first hit which is also a Sneak Attack, then your total damage for using a CANTRIP and not a single consumable resource is 24+16d6 sneak attack + 7d10.
That is pretty impressive.
You cannot use Sneak Attack on spell attacks, the feature specifies weapon attacks only. Taking Warlock for EB does nothing useful for a character built around Sneak Attack.
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Sneak Attack happens per turn, not per round. Any Reaction Attack made by a Rogue can already use sneak attack as long as it is made on another creature’s turn.
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I'd argue training to develop a shield proficiency isn't too much of a game-breaker, balance-wise. The argument of "if you give them an inch, they'll take a mile" doesn't really apply here, as the DM is god, so saying "yeah, you can train yourself to learn to use a shield, no you can't train yourself to cast wish" is just... responsible use of rule zero. If you want to create a measurable cost, then develop a side-quest to find a trainer, get a special shield, DO some kind of training exercise that challenges the player in their downtime.
That said, you could also talk to your DM about modifying the class to allow a little more flexibility. For instance, maybe you get shield proficiency, but you give up an expertise option, or 1d6 of sneak attack damage to reflect time spent away from roguish enterprise and focused on more martial endeavors. If you do this, make sure you give up something valuable in exchange for it. Saying "oh, I give up dagger proficiency for shield proficiency" is no good. You're giving up something you won't miss in exchange for a useful class feature. In general, if you feel like you're getting screwed on the deal, it's probably a fair trade.