This is Tony, who also goes by Bard or Ro. He doesn't like himself much, but he hates everyone else more so he keeps to himself. He goes to university even though he doesn't want to, mostly because his parents want him to. He's very cold and logical and tries to avoid becoming attached to the monsters around him because he doesn't have time for friends. Or at least that's what he tells himself, though in reality he just doesn't want anyone to have to be forced to deal with him and his baggage.
Ro refuses to explain why he 'fell' into the underground, though the fact that he distrusts everyone around him and is now scared of heights hints that someone might have pushed him. He uses an axe as a weapon, though mostly he just beats up anyone who attacks him until he has the chance to run away. So far he's avoided killing anyone, though he's working on tracking down that creepy fucking flower so he can commit a little pest control.
At least, that was his original plan. He's since learned that Flowey is just as apathetic as he is, so now he's dragging the sentient flower around with him on his journey. It's unsure to everyone whether they hate each other or whether they're the best of friends.