There's actually at least three girls who to varying degrees reflect different aspects of Tomoko. Nemo is geeky but gregarious and doesn't share her asshole tendencies (still a troll though), Yuri is gruff and unsociable but not geeky or eccentric (and doesn't mind being bit of a loner), and "little fang bitch" Minami - who ironically never directly interacts with Kuro - is kind of like her mean and selfish streak turned up without the nerdy eccentricities and massive social anxiety. Also similarly prone to digging herself into holes hilarity ensuing.