Back in the Mamodo World,Rein would always go on rampages until he accidentaly slip off a cliff near his village.  Waiting for death,another mamodo name Zatch was the only one who didn't fear him. After that he knew what true strength was. He, along with Zatch, was chosen to become the new king. He met a cowardly boy named Kyle,who he found being shot at by villagers and became his parther.Later on, he asked Zatch to burn his book regardless if he become king or not because of Kyle's cowardice, but he and Kiyo decide to help him instead. But regardless Kyle was caught by two other evil mamodo, Purio and Rodeaux. Seeing Zatch's strength he was able to show his true form in front of Kyle to get rid of his cowardice and become the same as Zatch.During the battle Kyle has found his inner strength and able to defeat to Rodeaux but not burn his book.Kyle was knockout the whole time but Rein still wants his book to be burn by Zatch telling him to become King.Rein was seen helping during the battle with Clear Note and is helping with orphanage house.
Kyle was a boy who was scared of everything and had to live in a hut all by himself because of his property manager Jill. He found a strange "monster" named Rein and decided to care for his wound. Both of them became best friend but as time roll by Kyle's fears become more and more great, even when Rein helped him against Jill. But eventually, when Zatch came to town to help, he was still the same until he found Rein's true form. After Rein's book was burned he got the courage to stand up against Jill and was able to stand on his own but even if Rein is not there he'll ask others people for help if his power not enough. Kyle was last seen dancing to see that Rein got his letter in the Mamodo World.
- Rein has the ablilty to change his form into a human
- Aborodio: A star-like beam is created from a swipe of his claw. (Attack)
- Aagasu Ahorodo: A claw shield spreads out to protect individuals. (Defense)
- Garubado Aborodio: Projects a giant image of Rein with four arms and gigantic claws. (Attack)
- Shin Garubado Aborodio:More powerful verison of Garubado Aborodio