Leon Luis is the bearer of the title Garo the Golden Knight, a Makai Knight who inherits a legendary suit of armor. He is the son of Germán Luis, the Makai Knight known as Zoro, and Anna, a Makai Priestess. He was born under traumatic circumstances: his mother was burned at the stake for witchcraft, and only her last-moment magic combined with his father’s desperate rescue allowed him to survive and escape the kingdom of Valiante. This event defines his entire early life, as he is haunted by recurring nightmares and visions of his mother’s execution.

These constant traumatic visions shape Leon into a bitter, mostly emotionless, and deadpan young man. He is quick to anger, highly distrustful of others, and largely naive about the wider world, which makes social interaction awkward for him. Despite this, he possesses a kind-hearted core. However, his kindness is buried under a deep apathy toward his duties as a Makai Knight. Initially, his motivations are not about protecting humanity from Horrors but rather using his abilities solely as a means of exacting revenge for his mother’s death. He sees the Garo armor not as a sacred responsibility but as a personal heirloom left to him by his mother. He also holds strong disapproval of his father’s womanizing behavior, viewing it as an insult to his mother’s memory, and will not hesitate to physically retaliate against his father if he goes too far.

In the story, Leon returns to the Valiante Kingdom as a young man determined to kill Mendoza, the advisor who orchestrated the witch hunts and his mother’s death. His path crosses with Prince Alfonso San Valiante, who seeks the help of Garo to reclaim his throne from Mendoza’s usurpation. The two learn they are maternal cousins, as their grandfather was the previous Garo. This relationship becomes central: Alfonso not only aids Leon but also temporarily strips him of the Garo title after a catastrophic battle. During the confrontation with Mendoza, Leon is overwhelmed by implanted visions of his mother and transforms into a Lost Soul Beast, a monstrous form whose inferno destroys the town of Santa Bard and harms innocent people. After being subdued, Alfonso confiscates his sword, the damaged Zaruba, and the Garo title, deeming Leon unworthy. Left mentally broken and without purpose, Leon attempts suicide by throwing himself off a cliff.

Leon’s development is marked by his journey from revenge-driven isolation to a genuine desire to protect others. After hitting rock bottom, he discards his obsessive need for vengeance and decides to become a true protector. He reclaims his armor and title, reconciles with Alfonso, and joins forces with his friends to continue fighting Horrors and eventually pursue the still-living Mendoza. This shift is a key part of his growth as a knight.

In terms of notable abilities, Leon wields the golden armor of Garo, which grants him enhanced strength, speed, and the ability to channel powerful flame-based attacks. He also wields a magical sword and is aided by the living ring Zaruba, which provides guidance and detection of Horrors. His most advanced form is Heavenly Sword Glitter Garo, composed of the collective will of past Golden Knights, which grants the ability to fly and deploy multiple detachable blades that can be directed remotely. Leon is also shown to have a strong inner flame that can surge out of control when triggered by traumatic memories, as seen in his Lost Soul Beast transformation. Through his journey, he learns to master these powers with greater discipline and purpose.