You'd need a different grip on the sword if itbwas supposed to be an upward attack.

Katana edge placement is fine. You're seeing the follow through of an attack.

Sword would have started up above his right shoulder, then was swung in a downward slicing motion ending at his left him. The front edge of the katana would have been in the right place for that.

Other stuff is off, but that's proper.

Yeah, the back shoulder is janked, and his right forearm looks like it's coming out his stomach.

That's just his left and right hand, my dude.

There's a bunch of other wonky stuff going on, but that's just a standard two handed sword grip

Maybe I'm dumb, but I definitely don't see a second set of fingers

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(I'm more of a Luigi guy)