Karneval (カーニヴァル) is a Japanese manga series by Mikanagi Touya, originally starting serialization in the monthly shōjo manga magazine Monthly Comic Zero Sum published by Ichijinsha in early 2008. There are currently four volumes released in Japan.
Nai searches for someone important to him, Karoku, the one that he calls "borther", 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"!!
Informations source: Wikipedia