Izaya, without a doubt, is an extremely crafty individual. He claims that he loves the whole human race because he finds them very interesting and unpredictable. He enjoys messing with them by manipulating situations in order to observe their reactions for his own pleasure. However, he dislikes Shizuo with a passion and enjoys playing with and has antagonized him since they met in high school.

His hatred of Shizuo stems from Izaya seeing him as something 'inhuman' or 'monstrous'. Shizuo is also