I think maybe he is a sadist or delinqent that wanna change himself to be a better person but he is not there yet. That's why he show his true self(?) Sometimes and ashame of it.
this is pm a spoiler so dont read further if u would rather wait for the scans of the next chapter
well basically what i could get from the raws with my basic jpn skills, is that rather than yacchan being a sadist or delinquent he has a huge inferiority complex towards kashima; he even says he yearns to be like kashima, all of yacchan's smiling is just a front to be liked. seeing how kashima has feelings for toono he intends to take him from kashima bcs he wants to win against him
Yes, he is
pls don't tell me he's a two-faced bitch D: