Maruss and Rembrant are a team who end up pursuing the team of Tia and Megumi early in the Mamodo fight. Their element is metal. Maruss was originally Tia's best friend in the Mamodo World, caring and looking out for her compared to her bullying ways against Zatch. But once in the human world, his mentality changes, believing that friends can no longer be friends due to the nature of fighting and must go against one another to become king. Rembrant is a power-hungry, blithering idiot who believes he can rule the world with his mamodo Maruss.
When Tia and Maruss meet for the first time in the human world, he betrays her and attacks her, sending her into the ocean. When Tia survives and is taken cared by Megumi, they start to pursuit her and attack them on many occasions, due to Megumi being a famous idol. While assaulting Tia in the midst of one of Megumi's concerts, Zatch comes to her rescue by standing up to Maruss until both their bookkeepers arrive to fight the battle against him. Ultimately, it is Zatch, the former "weakling" neither he or Tia cared for, who defeats the prideful Mamodo, (his shirt was all ripped) and forces Tia to change her ways about friendship in the heat of battle.