Basil is a pretty quiet/timid person, and also sometimes sensitive but he is someone who cherishes his friendships and expresses his comfortability in terms of photograph and holding onto memories of his friends and such, but he is also afflicted with his anxiety, guilt, and emotional openness as a result of what happened 4 years ago until present time.
However, Basil's personality takes a shift as he is put into not one, but two killing games; having experienced his friends and others dying has changed him in some way or not. He's now a bit more open and rather dedicated to stopping what masterminds were up to these games; he is also a bit more blunt and serious. Although he does keep his main traits, he can still show a new side of himself.