Actually, thunderbolt could work, i think it could work like this:
Skip to 4:10
I think it should be not a projectile, but a long hit box with big hit stun that.
Also, does anyone remembers the previous versions of sephiroth? how he could move the sphere at will anywhere?
If that could have reduced range, and become a hitbox with flame fx it will be perfect.
I was wondering, how about not giving him concrete pkmn moves?
I mean, some good PSAs have moves that don't have a name, and sometimes that character can use it, but never uses it in most of his games.
Like giving him a black hole move or something.