Triela

Triela has a sarcastic wit and prefers to wear masculine clothing. She serves as a sort of mentor/Mother to the other girls of the SWA and she retains the most realistic outlook on their situation.
Triela's preferred weapons are the SIG-Sauer P230 SL pistol (after losing her P230 to Pinocchio, she is given a 232-SL as a replacement) and the M1897 Trench Shotgun with bayonet attachment. She has also been shown using a selection of Heckler & Koch weaponry, including the H&K G3A3 battle rifle, the H&K P7M8 pistol, H&K UMP submachine gun and H&K MP7 PDW.

(Source: Gunslinger Girl Wikia)