S1·E10 Fate As A Warrior

A flashback episode, "Fate as a Warrior" shows Mahoro as a Vesper combat android, undergoing training and fighting her first battles. Endurance tests under various extreme environmental conditions, while too short to be truly useful, nonetheless succeed in giving her an appreciation of life, and her first battle is an overwhelming victory. The episode also shows fully the battle in which Cmdr. Misato, really the first person to accept Mahoro as more than merely a weapon, lost his life. It is the memory of his life - and his death - that really leads Mahoro to accept the full weight of her own existence, and to desperately want to continue living for as long as she can.