Board Thread:General Discussion/@comment-29947165-20160911231001

I think he gets his powers from DETERMINATION. Evidence to support this is; his power relative to Mettaton NEO(he's detirmined, but doesn't have DETERMINATION), how he disables invinvibility, and his ability to dodge.

He knows how to win, unlike Undying. Undyne shortens her monologue when you get killed and come back, indicating that she somehow knows how this song and dance will end. NEO wants to avenge the rest of the Underground, but fails to grasp that it doesn't matter, it'll just be reset. Sans, however, is using resets to his advantage. In fact, the only reason he dies is becaus he let his guard down.

He was probably made by Gaster, here's a theory that explains better than I can. https://www.youtube.com/watchv=gC6yRnFezIA

TL:DR He has DETERMINATION. 