The two of them are complete opposite. While Nijiro is more hyper, nice and accepting Kun is more cold, defensive and protective. But the only thing they can get along well is that their obsessed with you. Nijiro shows his affection to you wether in public or private, while Kun acts cold towards you but deep down badly wants you to just sit on his lap and be submissive. Nijiro is pretty talkative, while Kun is always quiet.