twinned witch bolt

sorcerer 3 can do a twinned witch bolt.

so the lightning mage starts with witch bolt, shocking grasp, lightning lure if he's a bit mental, and some other spells that do something else not lightning.

witch bolts a kind of garbage spell with a great name, and a great core idea. the idea is you might keep it up, as an ongoing attack over several turns, and it'll be like... like the emperor zapping vader, in reality, its easy to break, and its a lot weaker after the first turn, and sort of sits below the curve compared to like, a cantrip every turn.

the base case is 1d10 per target it hits, and 1d10 per target every round you maintain it. so at level one witch bolt seems good but its never really better than other options you get at that level. the beam thing is cool but its easy to break, and the damage is never really good.

if you twin it, at level 3, you hit both targets with improved initial damage and, if you keep it up, both targets with the ongoing damage.

lets say you're a lightning based caster with some static bonus to lightning, cast it with a level 2 spell slot...

2d10 + [your lightning] per target it hits, and 1d10 + [your lightning] per target every round you maintain it.

so the bronze/blue dragon sorcerer, sea sorcerer, storm sorcerer, have various weak iterations of this feature [your lightning]

these subclass feats say something like 'when you cast/hit with a spell that does lightning damage,' and so they dont interact well with witch bolt because they dont improve the damage on the subsequent turn.

you can't do bonus actions spells. the bonus action spells all cost concentration to maintain, except misty step, which breaks your witch bolts probably

so if [your lightning] was d6+cha its maybe be worth doing this thing. generally its just cha... is this, vaguely improved number, worth doing, on two targets for at least one round; and is [your lightning] also on both targets on the later turn... then is it worth maintaining as an action, because it doesnt need to hit again, and the sorcerer can quicken other spells. i think, if you had a real boost to lightning, witch bolt's a viable spell, just for the initial effect, and its sometimes worth maintaining concentration on. you can be the regular lightning guy using just witch bolt. and shocking grasp, you'd also have, as a disengage.

xanathars introduced dragons breath which is another spell you can do at sorcerer 3, which uses your concentration and costs a bonus action to activate, uses the target's action to use each turn, but the target can still take other actions, doesnt have to be you, hits enemies in a cone, and deals better lightning damage than witch bolt. (its actually like one of those pens which does four different colours, solving too much, because it can be fire, acid, lightning, poison, cold)  3d6/round, save half, and potentially hits lots of targets. i think most versions of [your lightning] will give it a boost on the first round but not on subsequent rounds, as with witch bolt. works with twin spell (twice the destructive power as this) or careful spell (hitting only enemies)

other level one lightning spells... well you got chromatic orb, which is another any-color-pen spell, and chaos bolt, which is great, but its another of these that can do any of multiple damage types. and you have lightning lure as a cantrip, which you wouldnt use unless you wanted to be in melee. maybe a lightning sorcerer can use lightning lure with quickened shocking grasp to pull someone into position and disengage? its not great. but its more damage per turn than witch bolt.

so the problem with witch bolt is its really not as good as other spells in its neighborhood, the things that improve it also improve those other spells, which is a shame because its a good thing to yell, 'witch bolt'

compare dragons breath which is not near as specific to the identity of your guy, unless, i guess, youre the dragon sorcerer. and which is a lame thing to yell