I'm pretty conflicted about Grand Caster. With their terrible damage multiplier, and the meta, the whole class really only leans into being supports. And I don't really like Castoria.
If I completely ignore gameplay, the Caster in the game I love the most is Gilles. So I think I will make Gilles my Grand caster. With the extra 1000 Attack, he might actually be pretty fun.
What about your Grand Caster?
Who will you pick?