Lena Isis is a Gundalian from Bakugan Gundalian Invaders. She is a member of Ren's team. Lena's Guardian Bakugan is Phosphos, and her Battle Gear is Terrorcrest. Lena still has a good friendship with Zenet. Lena was seen out of her disguise for the first time during Jesse's funeral service. In Season 10, Lena battled against Zenet. However, Zenet increased the stakes by enhancing Lena with the Smash core. While Lena was able to resist it, Zenet said that once Mason, who was watching the battle along with Jesse, coughed up blood, then the enhancement would overwhelm Lena. When Reiaz, who will play a bigger role in the future, suddenly appears claiming the odds aren't in Lena's favor, Lena then begins a counterattack against Zenet. However, Zenet's claim is true once Reiaz punches Mason hard enough that he starts coughing up blood, Lena is overwhelmed and corrupted. Lena is now an antagonist as a result. Lena and Zenet are the true final antagonists of Season 10. At the end of Season 10, the evil in Lena and Zenet's souls are toned down after Mason takes the Beam Sword, the Cleansing Rod, and the Millenium Rod from Lena. However, Lena and Zenet haven't been restored yet and are still antagonists. In Season 11, Lena realizes the error of her ways and returns to her old self. In Season 22, Lena is murdered by Meta Knight along with the rest of Ren's teammates. Lena is later revived in order to stop Samus Aran. In Season 26, Lena is brainwashed by Mechtavius Destroyer, who inserted a seed within her before his death, and acts as the main antagonist of Season 26, as she hires new villains, such as King Boo, Goomboss, and Chief Chilly, and old villains to try to stop the Heroes of Legend as well as creating clones of Mario known as Metal Mario and Mariyo. Lena is later freed when Ultimate Kevin absorbs the seed from her body, but is deeply traumatized as a result. Unfortunately, Lena is later corrupted by Psyphon after he duplicates the power of Mephiles the Dark and bestows it upon her, as Psyphon claims to see a lot of potential within Lena. However, Lena later snaps out of it after witnessing Phosphos die in an attempt to save her.
Lena is a tactical thinker when she is in battle, although unlike Sasuke, Vegeta, and Shadow, Lena isn't overly aggressive. She has shown excitement when it comes to battle, shown in Season 4 when she requested if she could battle Orochimaru after Kakashi was freed, and when she was told she could, Lena pulled her arm back while saying "Yes" and immediately proceeded to defeat Orochimaru. However, after getting corrupted, Lena is much more colder and heartless. In Season 26, Lena is brainwashed by Mechtavius Destroyer into carrying on his legacy, causing her to become more malevolent and twisted. Unlike Mechtavius Destroyer, however, Lena prefers to have others do her dirty work for her.
- Lena and Mariyo are so far the first, and only, characters that have defeated Mario in battle.
- Lena is the only member of Ren's team to have been an antagonist twice.