Square Root 3: Hitonami ni Ogoreya Onago

17 years ago, the "Conjurer of Calamity" bridged the gap between the human realm and the demon realms. Now, the world teems with other-worldly creatures and demons ranging from zombies to vampires to half-lizard men. Now after 17 years, these creatures coexist with the humans peacefully.

In the mixed creature school of "Banmaden," three students live their daily lives finding the oddities of their world. The "fox demon" Hisagi Hatsune, the "raccoon demon" Futatsuiwa Mami, and the "demon dog" Kousenji Hoyu search their school and town for mysterious urban legends to solve.

(Source: Mangahelpers)