DC Ultra is a Pixiv creator whose works follow the university student Anna Blackthorn, a girl who moonlights as a masked crime fighter but eventually unlocks the persona of a superhero, "Ultra." As the series progresses it features superheroines, fighting, defeats, humiliation, sexual humiliation and a whole lot more (and after a few works text included with an engaging story to follow). This was the first big Pixiv work, I'll be uploading more.

https://www.pixiv.net/en/users/13098329

Vol 1: Here
Vol 2: /g/2811481/5f0133ec90/