Gambino was the husband of Shisu, Guts' mother. When Shisu died Gambino took over responsibility of Guts. He trained him to become a mercenary starting at the early age of 6. Gambino did not really care about Guts. All he cared about was training Guts to not be useless and make money by killing soldiers on the battlefield. When guts was 9 he fought him first battle, the money he earned was then quickly taken by Gambino. That night Gambino earned a little more money by selling Guts for the night to a fellow soldier.
In the next battle Gambino lost a leg to cannon fire. he had to give up his position as leader, and could not fight. Now he relied on Guts for all of his money. One night two years latter, Gambino got very drunk and depressed. he went into Guts' tent and tried to kill him. Guts had to defend himself, and by doing so killed Gambino.