Kamui: One who represents the majesty of God; equally one who hunts the Majesty of God.
The destined savior of mankind, Kamui was raised by his mother, Magami Tohru, and grew up alongside the Monou siblings Fuuma and Kotori. All three of them were very close as children, but when Monou Saya died to birth the first Shinken, Tohru took Kamui to live in Okinawa so that their presence would no longer bring harm to the Monou family. The two of them lived in Okinawa where it is hinted that Kamui got involved in several physical altercations at school. For the most part they lived peacefully until six years later when Kamui returned to find his house ablaze and his mother inside. Using her own powers to prevent Kamui from saving her, Tohru directed Kamui to return to Tokyo to seek his destiny.
Upon his return, Kamui initially appears as cold, ruthless, and quite unsympathetic causing Daisuke, Arashi, and Hinoto to worry that Kamui might choose his destiny as a Dragon of Earth something later revealed to be an act to drive Kotori and Fuuma away to prevent them from being harmed. It's an act that fails miserably. Fuuma and Kotori remain steadfast in their desire to reunite with their childhood friend and help him. Kamui's ultimate goal is to retrieve the Shinken from the Togakushi Shrine and then to leave Tokyo again as quickly as possible. Kamui initially clashes with the Seals and Angels alike, resulting in several battles. After meeting up with Sorata, Kamui's violent behavior is tempered somewhat by his friendly demeanor.
After the brutal murder of Fuuma and Kotori's father, followed by the birth of the second Shinken, Kamui finally makes a decision as to which side he will fall on in the coming battle, becoming a Seal (Dragon of Heaven) and choosing to fight for humanity so that there would be a world in which Fuuma and Kotori could leave peacefully. This has the unexpected and tragic consequence of effectively erasing Fuuma's personality, awakening Kamui's opposite as well as Kotori being murdered by her brother in front of him. After this, he falls into a state of catatonia, brought back only by the newly arrived Sumeragi Subaru. Subaru retrieves Kamui's consciousness from the depths of his soul, the two mutually identiffy with each other, having lived through similar circumstances of the death of loved ones at the hands of a close friend or lover. Kamui loses some of his earlier coldness after being brought back, vowing to return Fuuma to his former self at all cost.
This Kamui is still determined, still prone to bouts of anger and restlessness but his demeanor has gentled, becoming closer to his fellow Seals and in particularly, forming an intensely close friendship with Sumeragi Subaru to the point where it might be suspected that Kamui has something of a nascent crush on the onmyouji. It's clear he feels responsible for not being able to stop his cataclysmic battle with Sakurazuka Seishirou and is clearly shaken when Subaru disappears afterward. Towards the end, Kamui begins to assume more of the burden and responsibility of leadership, taking a more active role and in some cases, coming up with his own orders when he starts to suspect that the Dreamseer Hinoto might be betraying them. He takes his failures harder though he tries to remain strong for the others, holding himself personally responsible for all the tragedies that have occured.
Though Kamui continues to maintain his wish is to return Fuuma to his true self, Fuuma in his role as the Kamui of the Dragons of Earth is able to see and contradict this assertion, stating that Kamui will not be able to win against him or generate a kekkai if he doesn't realize what his true wish is.