G.  

Giottos Right-Hand Man

G was Giottos childhood companion who helped form the vigilante group that became the core of the Vongola Famiglia. They resemble each other physically, including their shared smoking habit, and have a tattoo on the right side of their face. Initially, they carried a Gun as part of themselves, similar to Gokuderas Dynamite, but later switched to using a Bow given by Giotto. It seems that G has a closer relationship with Giotto than the other Guardians, particularly Tsuna and Gokudera at present.