Tremblar is a turtle-like BakuMine Bakugan with sharp defensive blades shielding its body. It detonates a stinging spike shield against nearby enemies, capable of cutting through even the toughest monsters. Initially among the ancient Nonet Bakugan imprisoned in the Doom Dimension, Tremblar and its fellow Nonets were trapped by rogue Mechtogan until freed by the villain Wiseman. It served as one of Wiseman's Guardian Bakugan alongside other Nonets like Betadron and Kodokor. After learning from Wiseman that Dragonoid descended from the Original Dragonoid who banished them, Tremblar agreed to help revive evil Mechtogan in exchange for revenge against Dragonoid and the Battle Brawlers. It battled on Earth in locations like parks and stadiums, frequently targeting Battle Brawlers' Bakugan such as Roxtor, Radizen, Skytruss, Orbeum, and Jaakor. Tremblar utilized attacks like Goliath Flugel and Grudge Cannon during these confrontations and often assisted in summoning the destructive Mechtogan Mechtavius Destroyer, though the Nonets repeatedly lost control of this entity. Tremblar later allied with Gunz Lazar following Wiseman's betrayal and the revelation that Wiseman was the Mechtogan Coredegon in disguise. Alongside remaining Nonets, it confronted Mechtavius Destroyer after the latter banished the Battle Brawlers to the Doom Dimension. During this final battle, Tremblar employed abilities like Lagrange Shield and Goliath Flugel to break through the Mechtogan's defenses, coordinating attacks with allies such as Scorptak and Kodokor. Its pod was destroyed, and Tremblar retaliated with Grudge Cannon before being killed and absorbed by Mechtavius Destroyer. Tremblar possessed ability cards including Goliath Flugel, Grudge Cannon, Lagrange Shield (called Lagrant Shield in Japanese), Boost Flugel (Faust Flugel in Japanese), and Gore-sin Oath (Gorsen Alt in Japanese). It displayed robotic traits such as scanning for enemies and experiencing system malfunctions when attacked. As the only BakuMine Bakugan among the Nonets, Tremblar could not fuse or combine with others. It never utilized a Battle Suit and remained the sole Nonet unable to equip BakuNano enhancements in related games.