tnx :) Anyway it's a pretty cute nickname for Ritsu.. :D
Actually referring to Kageyama because he was the one who defeated Hanazawa. Ritsu happened to adopt it because all them punks are attacking Salt Mid because of their reputation of White T Poison being a particularly powerful delinquent.
Coincidentally, this mysterious group hunting espers seems to think that Ritsu is Kageyama as well thanks to the Awakening Lab and their own intel lol