Theodore Glass, also known as Alexander Gilten (アレキザンダー・ギルテン Arekizandā Giruten) in Japan, otherwise known as his alter-ego, Ashtem, is the owner of the Snake Pit Organization and manager of the American team, the Raging Bulls in the series Beyblade Burst Evolution. He is very competitive with Kristina Kuroda, and her team, BC Sol; and travels the globe to gather the most powerful Bladers into his team. Because of his manipulations and intentions, he is undoubtedly the true main antagonist of Beyblade Burst Evolution.
Theodore is a young man, who has cyan eyes, and orange, dark brown, and white layered hair. He wears a white scarf that comes out onto his chest, he also wears a red shirt with three gold chains on the stomach area. He wears a black suit coat with purple folds,the top two folds are bigger than the bottom two. He wears black suit pants and black dress shoes.
As Ashtem he wears a black helmet like mask with black eye visors,three purple lines are on top of the mask and a red lightning strike is across the left eye and a red accessory by the right eye with two arms of the accessory going around the right eye. He wears a black coat with purple lining the end of the sleeves and purple spike designs on the sides of the opening of the coat.he wears black armor like gloves that have purple designs on them. He wears a black turtleneck shirt underneath his coat,the shirt has a purple line starting at the collar and continues down to a purple diamond with a smaller diamond inside,after this diamond the purple line continues down to a red belt. He wears black armor like pants with purple designs as well as black shoes, his pants have purple lines down the sides and purple knee pads on them.
Theodore is very manipulative and can convince others to agree with him easily. This is shown when he manages to get Free De La Hoya, the Number 1 Blader in the world, to believe that it is best to leave BC Sol; and allows Shu Kurenai's anger to change him into Red Eye. This is from the fact that he understands what motivates Bladers and uses it against them as their weakness. Kristina Kuroda, owner of BC Sol, seems to be the only one unaffected by his personality and shady manner. Both Kristina and Trad Vasquez, BeyTrainer of BC Sol and Kristina's advisor, are put off by Theodore's sudden visit to the training complex showing how much power he has over others.
Despite his shady behavior and manipulative ways, he can be honest as he upheld his promise to help Shu achieve the power he desired with no apparent ulterior motives.
As his alter-ego, Ashtem, leader of the Snake Pit Organization, Theodore becomes much more authoritative and unafraid to show his power a Blader can have. He believes that on the road to strength, one must weed out the weak and those willing to give up, no matter how merciless it would be to do so.
He structured the Snake Pit in a way where this belief would always be followed. He also seems to enjoy toying with Valt Aoi, Rantaro Kiyama, Cuza Ackermann, Daigo Kurogami, and Wakiya Murasaki when they are within the Snake Pit, watching them lose for the sake of research. He also confronts Shu Kurenai after his loss to Free De La Hoya, and uses his moment of weakness to convince him to become part of the Snake Pit Organization as the sinister Red Eye.
- "I know what you truly desire." - to Red Eye, as Ashtem, after Valt and his friends are kicked out of the Snake Pit
- "You've done well, Red Eye. Very impressive. Keep up the good work and soon, victory will be yours. Then, the last phase of the Requiem Project will be complete."
- "I concede. You and Valt have won...this time." -last words to Kristina in the Evolution season finale
At first, Theodore doesn't think much of Boa, as he is just a starting blader. He tells him to be quiet and observe as the Shadow Bladers fight Valt and his friends, and tells him that if he gets stronger, he can soon get more power of his own. Theodore also believes that Boa may be the only Blader to defeat Red Eye.
Theodore has some respect for Norman, as the latter is second-in-command in the Snake Pit. He seems confident that Norman will do his best in Beyblade. However, it is implied that Theodore may be using him.
- He's the Burst series equivalent of Boris Balkov and Doji from the original series and the Metal Saga respectively.
- His multi-colored hair may be a reference to characters he manipulated. The brown part being Trad, the yellow being Free, and the white being Shu.
- His name being changed from Alexander to Theodore in the dub was likely to avoid confusion, as Xander Shakadera's real name is also Alexander.