[Chaos]

The only thing overpowered about Asura Fist is how it gives twice as much Sturm. I see no issue with bumping it down to +1 Sturm, and possibly increasing the FP cost.

The damage, while potent, is still under one of the easier elements to resist, and anyone can easily keep Sturm from going wild if they know how to maneuver. Without that additional Sturm boost, I wouldn't call this anything more powerful than an Evoker/Hexer's Eternal Darkness, especially if your setup isn't fully committed to Boxer.