|First appearance||The Battle Begins|
Siege (Japanese: Knight ナイト) is a knight-like Bakugan.
Siege is a knight in shining armor. His silk cape is used both for flying and protection. He is equipped with a lance with different blade tips depending on its attribute.
In the anime, Dan and Kenta had Pyrus Sieges, Runo and Joe had Haos Sieges, Masquerade had a Darkus Siege, Marucho and Jenny had Aquos Sieges, Jenny's is her Guardian Bakugan, another Aquos one was used by an Illusionary Marucho, in Marucho's test set by Frosch. An Aquos Siege was also used by Rikimaru, given to him by Masquerade to defeat Dan, but lost it. Jenny once called Siege "Aqua Guru" in the episode The One Hit Wonders. It appeared in Bakugan video game.
- Ability Cards
- Tsunami Wave: If you have three Aquos Bakugan on the field, every Bakugan on the field besides Siege automatically loses. (Aquos)
- Aquos Javelin: Switches Gate Card with the one next to it. (Aquos)
- Water Refrain: Prevents the opponent from using abilities for a short time. (Aquos)
- Dive Mirage: Allows Siege to move to another Gate Card and nullifies the opponents Gate Card. (Aquos)
- Fire Sword: Adds 100 Gs to Siege. (Pyrus)
- For each attribute, Siege carries a different form of weapon in Bakugan form.