Can a Hexadin make good use of Booming Blade past Paladin 5?

[Segev]

Once a Hexadin has Extra Attack, is booming blade useful? Particularly if they have Polearm Master. (I'm investigating this for an actual PC in a game I'm in.) The trade-off of a bonus action attack for booming blade's extra damage before you have extra attack, especially if you're splitting levels so that you're level 5 character before you're Paladin 5 and thus get the benefit of extra damage dice from booming blade, may balance out...maybe. But once you have Extra Attack, is giving up 1-2 attacks going to be worth the extra damage from booming blade? Is the positional control going to be worth it?

[Dualight]

Short answer: It depends.

Longer, more helpful answer: It becomes worse for raw, consistent damage, especially if you manage to go far enough into paladin for Improved Divine Smite it kick in, but it probably will retain some benefit for keeping a single foe from moving. Before paladin 5, but after character 5, it will depend on your hit rate and the ability modifier you add to your damage, with the break-point being when the average damage of your bonus action attack exceeds 4.5. So the question is, how much do you value the control effect of booming blade, and how important is it to have a source of thunder damage? (If earth elementals or other creatures with vulnerability to thunder are common, booming blade remains valuable for far longer, whereas in a campaign where thunder resistance is common, booming blade is nearly useless.)

[follacchioso]

I don't think you can cast Booming Blade as Opportunity Attack; not even with Warcaster, because the target is Self, not a creature.

[JNAProductions]

I don't think you can cast Booming Blade as Opportunity Attack; not even with Warcaster, because the target is Self, not a creature.

Ask your DM. It might not work RAW, but I'd be fine allowing it, and I'd imagine many others would be too.

[LudicSavant]

Ask your DM. It might not work RAW, but I'd be fine allowing it, and I'd imagine many others would be too.

It just works RAW.

I don't think you can cast Booming Blade as Opportunity Attack; not even with Warcaster, because the target is Self, not a creature.

You're thinking of the Range, not the target. The Range line in a spell description does not tell you the spell's target.

If something has Range: Self (100 foot line) that doesn't mean that you target yourself, it means the range is a 100 foot line extending from your space.

In Booming Blade's case, the Range is Self: (5 foot radius), which means the range is anywhere within 5 feet of your space (no matter how big your space is).

If the target willingly moves 5 feet or more before then, the target takes 1d8 thunder damage, and the spell ends.

[Hael]

1handed hexadins frequently make great use of booming blade via warcaster. Its slightly more rare to see warcaster for 2h builds (especially post Tashas now that there are invocations like eldritch mind), but even with a 2hander, it might be worth it if you can dissuade the enemy from B lining towards a target other than yourself.

[diplomancer]

Maybe a Goblin Hexadin, who gets to Booming Blade and Bonus Action Disengage?

[Reach Weapon]

I don't think you can cast Booming Blade as Opportunity Attack

In Booming Blade's case, the Range is Self: (5 foot radius), which means the range is anywhere within 5 feet of your space (no matter how big your space is).

Particularly if they have Polearm Master.

Segev and I may have found a way to break it.

[5eNeedsDarksun]

Hmm, does the Hexadin have a Familiar? One bigger attack with advantage could start to = 2 smaller attacks (one of which with advantage), particularly vs higher AC targets. Though it's also BA dependent. Before going BB I'd have to be doing something else with my BA, like casting a spell, as in all likelihood by level 5 using the attack action would trigger a BA attack.

Pretty niche I think.

The other argument against is the Smite factor. The more dice a Paly is rolling the more chances of a 20, which you'd likely use as an opportunity to smite.

[Keravath]

With polearm master I would lean towards No ... booming blade doesn't provide a lot of utility.

PAM requires the character to use the Attack action to trigger the bonus action attack. So on their turn, the character would be using extra attack to get three attacks (especially with IDS at later levels) rather than a single attack with booming blade.

The only real utility then for BB comes from using it for the OP attack provided by PAM in concert with having the Warcaster feat. PAM gives an op attack when a creature enters your reach. However, BB only has a range of self (5' radius) so it doesn't work with 10' reach weapons (which would give the opportunity to force the target to take the BB rider damage when moving to 5'). The creature is unlikely to keep moving once it gets to you so it is less likely to trigger the rider BB damage. So all BB is doing in this case is adding a d8 damage/tier after tier 1 - which probably doesn't make it worth the investment in Warcaster. On the other hand, if you have the Warcaster feat anyway, it is probably worth keeping BB for those occasions when you can use it for a bit more damage on an op attack.