The Monster Master's Legacy (怪獣使いの遺産 Kaijūtsukai no Isan) is the 32nd episode of Ultraman Mebius.
At the beginning of the episode, we see a grown boy digging a large hole by the riverbed who is encontered by a girl who which the boy says he is trying to find the spaceship of and Alien Mates (the original killed during Jacks time on Earth). Years later in Mebius' time, a saucer is seen landing in the Takuma Mountains and Miari and Ryu are deployed there.
Separated from Ryuu, Miari finds a young Alien Mates named Bio who is trying to set negotiations with earth and wants to establish peace. It is shot in the arm by Ryu who thought that the alien was attacking Miari. Enraged, the alien summons the saucer to attack the near by city. Meanwhile, GUYS learns of the story behind the original Alien Mates, who was shot in cold blood for being and alien.
Meanwhile, the alien hides inside a building and takes a human form and is seen by a kindergarten class (Konami's) and is surprised by the kindness of both students and teacher alike trying to heal his wounds. Later he is found by Miari and Ryu again and both ask to have the saucer stop attacking but, full of rage he ingnores and Miari is forced to transform into Ultraman Mebius despite agreeing he would not get involve due to this being between Earth and Planet Mates.
Angered, the alien summons Zoa Muruchi and attacks. Still trying to convince the alien, he tells them he would not for that his hate comes from the fact that the old man who was killed by humans was his father and the fight between two giants insues anbd worse the new monster due to his new modifications is beating Mebius in the fight.
A light of hope comes in as the teacher of the group discovers who the alien was and tells of a "boy" who would want to have humans and mates shake hands together in friendship. Giving in he pleds to the silver giant in a downfall of rain to extinguish his hate and destroys Zoa Muruchi with the Mebium Shoot. Later that day the clouds clear and a rainbow appears in the sky as the alien with new light on humans goes back to his planet with hopes of having the two civilizations become firends in the far future. Going back 33 years ago at the end the teacher tells that the "boy" either died of a illness or left for someplace else but, she knows of where the boy truly left to.
- Ultraman Mebius Volume 8 features episodes 29-32.
- This episode was later featured in New Ultraman Retsuden episode 20 "Mebius and Alien Mates: The Monster Master's Legacy."