Taichou no Zaku-san

A bumbling but earnest and well-meaning mass-production Zaku II—despite holding rank and his best efforts, he received little respect from his newer-model men.

After he loses the Gyan of his dreams and later his captainship to his subordinate, he becomes heartbroken and depressed, drinking away his misery—going on a drunken tirade that sees him demoted and later reassigned／shipped off to the desperate frontline at Jaburo, on Earth.

He returns from the experience a battle-scarred and incredibly capable warrior (but still just as bumbling as ever)—wielding three bazookas tied together into a single weapon and a heat hawk bigger than he is—more than proving himself by single-handedly fighting and forcing the Gundam to retreat.

For his actions, he is promoted to commander of the Solomon Base—though the job ends up mostly consisting of desk work.