GANON1025
Although arguably, all of his spells are up for interpretation, he has canonically won a tournament of spellcasters almost entirely on the strength of Sun of Nothing, with the prevailing interpretation being that the spell was an annihilating sphere with the power of a sun. Even if I didn't think that spell was relatively fixed in what it does, I don't buy the power of luck stealing shifting the spell to a different user interpretation of it. Vriska looks like she easily stomps Ganon if this fight actually lasts, but he can oneshot her with Sun of Nothing and from what I remember, opening with Elemental Sun of Nothing was pretty much his only strategy.