Ep. 1: Gremory group hunts devil Maverick who creates Chimeras while Issei investigates student anemia cases.

1

The Gremory group hunts a stray devil named Maverick, sending him to stand trial in the Underworld after discovering he worked in a lab developing Chimeras. The next day, Issei wonders about Maverick's parting words while overhearing that many school girls are getting sick with anemia. He notes that all the victims possess the same characteristic. Upon finding the source of the illness, Issei wants to protect it after learning its special ability. However, the rest of the group disapproves strongly, especially as some of the members are about to be inflicted with the same illness.