>>280346319
I don't think he says "one of us." He says ちなみにドＭです, which means "By the way, I'm a masochist." He doesn't use a nominative pronoun, but in Japanese when you omit that, unless further context suggests otherwise, it means you're speaking in the first person. Okarun and Kinta reply "WHO?!" as incredulous, not inquisitive.