Karneval (カーニヴァル) 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.
Plot
Nai searches for someone important to him, with only an abandoned bracelet as a clue. Gareki steals and pick-pockets to get by from day to day. The two meet in a strange mansion where they are set up, and soon become wanted criminals by military security operatives. When Nai and Gareki find themselves desperate in a hopeless predicament, they encounter none other than the country's most powerful defense organization, "Circus".