I really like how the guy senpai is someone who recently met Tsubasa, yet already has an affectionate nickname for her and seems to care about her genuinely as a friend with no romantic notions attached. There's not enough of that in stories I read.
he already knows her.. he demands others to change his name in front of her.. and couple chapters ago.. shows that Tsubasa knows someone with his "original" name..
@fodaobr22 omg..... I completely forgot about that..... hmm
edit: went back and checked, I think he knew of her but he did only just recently meet her. I still don't think he has any romantic notions towards her either