
I don't know if I can say he was all sweet to anyone around him (for Chiwoo, okay, tough he never abuses Chiwoo before,, Chiwoo already know how violent Jihyun is,, and always tells him not to trouble others in class).. I can't consider him yandere in the sense that he was never sweet or shy rather was violent and aggressive from the get go... Nevertheless I agree with you in this that He's not fully a Tsundere either..
He has Tsundere characteristics : keeps switching back and forth between being cold and warm to Chiwoo. He's also passionate, wild, and aggressive too.
And has Yandere feature also : dark and obsessive over the one he loves. use violence on, and possibly even murder, any person who gets close to his love interest..
So maybe he's the combination of these two dere characteristics..
am i the only one who feels for jihyun? i know he's bein a dick but with all that he's been through i wouldn't be surprised... my heart aches for him... i hope he finds someone else tho... someone else who will treasure him more... someone who can teach him that being venomous to everyone else is not the answer to everything... i wanna give him a hug... (づ ̄ ³ ̄)づ