阿良々木 暦, Arararagi-san, Koyomin, Koyokoyo, Oni-no-Onii-chan, Thrall of Heart Under-Blade
Age: 18 Birthday: 14th April Height: 165 cm Weight: 56kg Koyomi the main character of the story is a third year high school student who is close to failing every class except math. He is an ambidexter because he usually uses his left hand but he writes with his right hand. Other characters seems to speculate that Koyomi is a lolicon particularly Mayoi and Hitagi with Hitagi thinking that Nadeko is a threat to her. Koyomi is the only person who thinks that his family relationship is bad with Karen and Tsukihi thinking otherwise. Koyomi Karen and Tsukihis parents were also revealed to be police officers.