Colonello is one of the Arcobaleno. He is a skilled marksman with a military background.
Colonellow and Lal Mirch before their transformation
Unlike the rest of the Arcobaleno, Colonello was not meant to be an original member of the team. He took the spot of Lal Mirch because he cared for her and didn't want her to suffer the duties of an Arcobaleno. Because of this he is now the holder of the blue pacifier of Rain. After becoming a member of this organization he was put in charge of the training ground at Mafia Land. Because of this he has become a tutor to other characters in the series, the first being Ryohei during the Varia arc where he taught him how to be a Guardian of the Sun. This training began with the two of them just laying on the ground and staring at the sun, giving Ryohei's body time for his cells to heal themselves because thanks to all of his training he couldn't quite reach his full potential because his body hadn't yet adapted to the level of power he had.
Colonello carries around a giant anti-tank rifle that is his weapon of choice.
Like the other Arcobaleno he has an animal companion, his being a falcon that can fly him anywhere.