BLUE

The development of the large robot "Walker" has ushered in a lawless age of endless conflict. Following his grandfather's will, a young boy named Jean searches for "Blue," a man who holds the secrets of his family. One day, he is saved by a mercenary with beautiful blue hair, who is oppressed as a low-ranking member of a band of thieves. By chance, the man ends up working with Jean, calling himself "Blue," but... A robot action movie set in the midst of war that depicts the lives and troubles of mercenaries!!

(Source: Scroll Book, translated)