Oh, just realized the PERFECT person to kill Accelerator with!
He won't be animated for another month or two, but meet Kujo Jotaro, also known as JoJo the third, from
Jojo's Bizzare Adventure.
You see, a "Stand", your super-powered shamanic guardian spirit which is a projection and reflection of your soul, although incorporeal and hence can't be touched by the white-haired little psycho, CAN very much touch and indeed SMASH any physical enemy who has no stand of his own to defend himself.
With the Stand known as Star Platinum projected before him, JoJo can pummel Accelerator with HUNDREDS of steel shattering ghostly-punches a second, NONE of which can be fought back against or even reflected unless cutie-murdering sociopath here learns to be spiritual and gets a Stand of his own.
So-called most powerful, you have once again met your match.