My Booming Blade Focused Eldritch Knight

I wanted to build a EK fighter for a new campaign that starts at 1st and goes to maybe 10th but one that focuses on very high survivability, good damage pacing, and the ability desire to tank and kite as much as possible. I haven’t seen a build quite like this yet and through I would share it so others can critique it before the game starts in case I overlooked something.
Since this is a build I plan to play level per level I tried to think about how each level will play out instead of building for a specific skill that won’t hit until 7 or 8th level or something like that. The one odd catch is our DM gave us 30 points for our stat buy because the other 3 players are new to the game and wanted to give everyone a slight edge, but not a huge one. Knowing the EK is a bit MAD I am choosing to focus on the rapier and weapon finesse so this is a dex based build. This helps with using a crossbow as a ranged weapon, I can use a shield and gain the armor, and it stacks to help with acrobatics and also higher initiative (which is really important to me in this game since it’s so hard to raise). Then I chose Human variant with points in dex and con and the trait Defensive Duelist (easily clearing the prereq). Choosing the basic outfit of chainmail, rapier and shield, and light crossbow then selecting the fighting style of Defense. For first level my stats look like this:


Str: 13 (+1, 5 points)
Dex: 16 (+3, 15+1 human, 9 points)
Con: 16 (+3, 15+1 human, 9 points)
Int: 14 (+2, 7 points)
Wis: 8 (-1, 0 points
Cha: 8 (-1, 0 points)
Speed 30ft
HP: 13
AC: 19 base, 21 Defensive Duelist (16 chain mail + 2 shield + 1 Defense fighting style + 2 proficiency bonus on DD)
Melee: Rapier +5 atk, 1d8+3 dmg
Ranged: Light Crossbow +5 atk, 1d8 + 3 dmg


Ok, so that’s the base 1st level, 2nd level only adds action surge, so that’s that. At 3rd level is where it starts to come together. Take Eldritch Knight, bond with shield and rapier, cantrips are Minor Illusion and Booming Blade, 1st lvl spells are Shield, Absorb Elements, and Find Familiar (for my any spell on list choice). The main idea of the build is to basically spam BB whenever I can, then move back 5ft away from the enemy. This invokes an attack of opportunity but since they can only be melee attacks I’ll pop the Defensive Duelist as a bonus every time to raise the AC up to try and avoid the damage. This forces the enemy to move somewhere to attack assuming it’s melee (which at low levels most are) and triggers the 1d8 thunder damage. A 21 AC is really high for a long time level wise and will go up with better armor and proficiency bonus increases over time. If I’m fighting a boss then I can bonus action on Shield instead and jump to 24 AC for one round if I need the real save (or Absorb Elements). At 4th level just throw the +2 stat into Dex and bump up to +6 atk and 1d8+4 dmg on melee and ranged attacks. At 5th level it gets interesting because BB does base 1d8 thunder on the atk plus its usual 1d8 on movement of the enemy. But I also get 2 melee attacks per attack action if I want to go that route. So the choice is 2x1d8+4 (15 avg dmg) for 2 melee attacks or 4d8+4 (18 avg) with BB (at 5th the spell does 1d8 on attack and 2d8 on enemy movement) for one attack if I can kite him afterwards. The thing I forgot to mention is that my plan was to use a familiar to use the help action on it’s turn to give me advantage on the first attack per round when I can almost guaranteeing a hit with the BB versus less of a chance to hit with the second melee action (plus at 5th the proficiency bonus goes to 3 so DD ac rises to a min of 22). I feel I’d rather bet on the more constant damage than chance of missing half the damage but only if I can kite him at least 5 ft. This particular trade only lasts 2 rounds before the War Magic makes it no issue though since I can use BB and then another melee attack.


The main plan is to use ridiculous armor score to attempt to kite melee enemies to trigger the full damage of BB and see how it scales with level and other abilities. With using a familiar as help it should hit very often and with DD I should get hit not very often. Once it gets to higher levels I figure enemies will lean on magic and ranged attacks more often and the extra attacks per round might just work better tactics and math wise since if I can’t trick them into moving then it won’t trigger that extra damage. It’s not a big deal to drop to just full round attacks if I don’t think I can kite the enemy, like a wizard or something with primary ranged attacks. Since BB scales pretty well and DD also is based on proficiency bonus I feel like this sort of build might work for many levels. What are everyone else’s thoughts? Am I missing something here that makes this not work that well or does it just sound too gimmicky to be fun or functional?

Make sure that you have the GP, rare incenses, etc to recast Find Familiar.

Why not take Spell Sniper instead?
It gets you Booming Blade from level 1, and doubles it's range so you could pick up a Whip (or Glaive/Halberd I guess) and not worry about taking any hits unless they've reach.

Remember that Defensive Duelist only applies to one attack roll per round, so its usefulness tends to fall off as more and more monsters start to get multiattack. That said, you've still got very respectable AC. Perhaps a 2 level dip into Rogue could be worthwhile for Cunning Action (bonus action disengage every round), since you already have high Dexterity.

Another option for abusing Booming Blade (although this requires two feats and thus level 4) is to take the feats Polearm Master and War Caster. Polearm master states that whenever a creature enters your (10-foot) reach, they provoke an opportunity attack from you, and War Caster lets you cast a spell for that opportunity attack as long as that spell targets only the creature that provoked. So when a creature gets within range, you can hit them with a Booming Blade, and if they want to close the distance to you, they have to move the last 5 feet towards you and thus are forced to take the extra damage.

Gavin O. said:

Another option for abusing Booming Blade (although this requires two feats and thus level 4) is to take the feats Polearm Master and War Caster. Polearm master states that whenever a creature enters your (10-foot) reach, they provoke an opportunity attack from you, and War Caster lets you cast a spell for that opportunity attack as long as that spell targets only the creature that provoked. So when a creature gets within range, you can hit them with a Booming Blade, and if they want to close the distance to you, they have to move the last 5 feet towards you and thus are forced to take the extra damage.

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Three feats; you also need Spell Sniper to cast Booming Blade at a target more than 5ft away.

I thought Spell Sniper only worked on ranged spell attacks. Am I missing something?

[MENTION=6700838]CS[/MENTION]S: Yea, I'm aware of the material and for the most part I don't think it will be a big deal. I can also just buy scrolls of the spell and not worry about the material components as well. I know that an owl will be quit squishy but if it dies it at least absorbs an attack that would have been on me anyways. I'll probably attempt the scroll route more than using one of the very few daily spell slots to recast anyways. I assume as the level rises it will die a lot. If it starts getting crazy I can reassess. Depends on DM really.
[MENTION=6780961]Yunru[/MENTION]: The issue is that the prereq for spell sniper says I must be able to cast at least one spell already. At first level you can't so the first opportunity to take it will be 4th level. It's not a free spell for a non spell casting class. The glaive and the halberd are both heavy 2 handed weapons which means I cannot use a shield (down 2 AC), have to respec for a strength build, which drops initiative, and drops my crossbow attack and damage, and cannot use Defensive Duelist because it's not a finesse weapon. The whip is cool but it's only 1d4 and unless you have the spell sniper then it's reach won't sync well.
[MENTION=1732]Gavin[/MENTION] O: Yea, the action economy of the DD is a bit weak because it's the Reaction slot so only once per round so my plan was to primary use it only when I move away and trigger AoO. Since DD only works again melee attacks and you can only perform a melee attack (unless they have certain spell abilities or otherwise) on attack of opportunities. I figure I'm I'm going to intentionally put myself into more harms way to trigger the BB then I should have a way to mitigate that. Every situation will be different so if I don't think the enemy is going to follow me then I won't be stepping away from it, but that's basic tactics really. Also since Shield and Absorb Elements also live in the Reaction slot I need to be aware if I plan on using them. But really I won't be using them that often since spell slots are pretty low and they return only after a long rest. So only use in case of emergencies. I could attempt to go for the Polearm Master route but to keep the finesse then I can only use the whip. With the 3 feats, the drop from 1d8 to 1d4, no ability score bump at 4th so no +4 attack and damage, and at least lvl 6 before it comes completely online it way loses to rapier and lower AC bonus. Or I can use halberd/glaive, and then it's str based with no shield so even less AC (no shield, no DD), ranged damage drops (way lower dex bonus), lower initiative bonus (less likely to be first to strike in combat), and only slight bonus to damage with the same level of gimmickery but less AC to handle when it fails. That many feats puts me behind on stat bonuses too.
[MENTION=62336]shadowoflameth[/MENTION]: the Spell Sniper also says "When you cast a spell that requires you to make an attack roll, the spell's range is doubled." so since BB only is against a single target and requires a attack roll (from the physical attack) then it doubles from 5ft. to 10ft.

I think as the levels go up and more enemies use ranged and magic attacks it will work less and less. But I honestly don't think this game will last that many levels. Certainly no more than 10.

I've thought about some of these other paths to but they are good points to consider for sure and exactly the kind of critique I was looking for.

shadowoflameth said:

I thought Spell Sniper only worked on ranged spell attacks. Am I missing something?

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Booming Blade is a ranged spell.

thebestjessins said:

The issue is that the prereq for spell sniper says I must be able to cast at least one spell already. At first level you can't so the first opportunity to take it will be 4th level. It's not a free spell for a non spell casting class.

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Well... feck. Kinda forgot about that. Still, I suggest taking it and a whip at level 4.

The glaive and the halberd are both heavy 2 handed weapons which means I cannot use a shield (down 2 AC), have to respec for a strength build, which drops initiative, and drops my crossbow attack and damage, and cannot use Defensive Duelist because it's not a finesse weapon.

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Eh, I only mention them because someone mentioned using Polearm Master to OA with Booming Blade on approaching enemies.

The whip is cool but it's only 1d4 and unless you have the spell sniper then it's reach won't sync well.

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1d4 really isn't that bad of an offset. It's 2 points average per attack off of the Rapier (which itself is overly strong of an option), and only 1 point off of the more reasonable finesse weapons like scimitars and whatnot.

It says Booming Blade is a range 5ft spell that you have to deliver with a melee weapon attack. Does that count as ranged? Ha, not sure, but it's funny if so. I figure if the DM is going to give me whatever basic weapon I want to start the game with I might as well choose the rapier. I went with the background of being noble so it would make a small amount of sense for being trained and affording one. I was reading someone else was trying to figure out how to use shield mastery to knock down opponents to force them to stand up and trigger the BB but turns out the rules don't consider standing up as movement even though it burns 5ft of movement. Like BB is a weird one to trigger the extra damage because an enemy that is right next to you and doing melee he's not going to move away from you ever. It also sort of works as a way for force them from ever moving away because if the DM knows it will damage the enemy and it does melee anyways then it's pretty much locked onto you. So it does work as a weird battlefield control effect that forces them to focus on you primarily. But green flame is also hard to trigger because you have to be in a crowd for it to work, it only moves to other enemies 5ft from the first enemy but won't travel like say chain lightning so it's so conditional and the enemies have to be really dense around the first enemy. And I try not to purposely get that surrounded, seems super dangerous.

I don't get buying 13 STR if you're only using it for chainmail. 13 STR won't let you wear the better heavier armor (unless you spend an ASI on it), and once you get your first ASI and to bump up dex you get the same AC from studded leather and your +4 dex, then get better AC from studded leather when you take your second ASI. All you get from the 13 STR is +1 AC from levels 1-6, and I think I'd rather have a better Wisdom to help with saving throws.

Also, you really need to take War Caster at 4th level to make your spells work. Without war caster, you can't use shield or absorb elements when you're holding a weapon and shield, so your casting side won't usually be able to contribute.