Blue Dragon, known as Karot, commands the Fortress Knights and wields the power of the Blue Dragon spirit. Once a timid young tank during the First Fortress War, he found inspiration in Resistance leader Oracle. Witnessing Oracle's murder by General Mangto Mantis drove Karot to flee initially, but he soon resolved to honor Oracle's legacy by becoming a courageous warrior.

Dedicating years after Oracle's death, Karot traveled across villages protecting civilians while rigorously training to master his abilities as a Fortress Knight. He formed his team by recruiting Duke, the White Tiger Knight, during a desert encounter, and later added Dig & Dug.

Karot led the pivotal assault against Dark Fortress at the Tower of Babel. There, Dark Fortress activated the crippling Super Spacetime Bomb, disabling Karot's Fortress Rise functions. At this critical moment, a human boy called the Stranger (later Yuma) emerged from a wormhole and bonded with Karot. This bond instantly healed Karot's injuries and restored his Fortress Rise. Empowered by Yuma's technomancy, Karot generated a protective force field. Guided subconsciously by Yuma, he united his team to unleash the Infinite Spirit Trinity Laser Sword. This combined energy beam clashed with Dark Fortress's second Super Spacetime Bomb. The resulting explosion destroyed the Tower of Babel, and Yuma's powers teleported the knights to safety.

Beyond combat, Karot prioritized civilian rescues during missions and demonstrated strategic acumen, such as during infiltrations of enemy strongholds. His bond with Yuma remained central to his effectiveness, as Yuma's technomantic abilities continuously enhanced Karot's powers, enabling advanced transformations and energy manipulations crucial to countering Dark Fortress.