@Doomer it's so he can say "I picked up the orb in the A ranked dungeon" (orb being the one he actually found in the hell gate but can't sell as an e rank cause it's too strong and doesn't have an s-rank title yet). now he can say that when he sells it without it being to suspicious
@Shewy92 2 things:
1- to me a wacko is someone who does things for no reason or simply because they can whether it be something "bad" or something "good". To me he is just twisted (up to you to view that as better or worse than wacko) and that is due to his past
2-prognosis comes from diagnosis...
@chenando1 calling him a wacko is a bit much i think. part of the reason he is like he is is cause his mom walked out on them when he was young so he has a peculiar view of roles and responsibilities especially when tied to love. and maybe something happened to natsumi after she transferred and...
@kronix i'm pretty sure he/she is a he (the rest of this will be assuming that he is in fact a he). he has been in the story since the beginning but more in the background hence his nickname "extra guy". natsume ai (the girl in the photo) is their friend since way back but she was picked on...