Bakugan Battle Brawlers (2007) : 3x7

Marucho frantically searches Bakugan Interspace and his home for Ren, but comes up with nothing. Meanwhile, Ren meets up with Sid, Lena, Mason, Jesse and Zenet, scolding Jesse for giving away his cover. Marucho uses a secret message to get Ren to meet him and they battle. Meanwhile, Fabia tells everyone her side of the story. Neathia was attacked by Gundalia and, due to their bakugan's inexperience in battle, they quickly lost to the Gundalian Bakugan. Fabia then sent out a distress message via the Phantom Data which lead her to BI on Earth. Shun discovers the battle going on between Marucho and Ren. When they arrive, Marucho defeats Ren. Ren attempts to get Marucho to switch sides, but he refuses to leave his friends. Ren declares their friendship over and reveals his true Gundalian form and tells Marucho that the next time they meet, they will be enemies.