Karneval.

About Karneval

Karneval is a Japanese manga series by Tōya Mikanagi which began serialization in the monthly josei manga magazine Monthly Comic Zero Sum published by Ichijinsha on August 28, 2007. There are currently twenty-eight volumes released in Japan. The series follows Nai and Gareki, who join a defense organization called Circus in hopes of finding a man named Karoku. However, they are unaware that Karoku belongs to a secret organization called Kafka, which is responsible for performing human and animal experiments called Varugas. A 13-episode anime adaptation by Manglobe aired between April and June 2013.