Keisei Tagami helped raise Ouri Kagami and is the contracted monk for the Shikabane Hime Makina Hoshimura.
Keisei found Ouri abandoned when he was just 3 years old. Keisei took him in and raised him at the orphanage he ran. Though they're not blood related, Keisei and Ouri think of each other as brothers.
Keisei was raised by the Hoshimura family when he was a child. After they died in a Shikabane attack, he became the contractor monk of of their daughter, Makina, who had been reborn as a Shikabane Hime. Keisei will do whatever it takes to help Makina reach her goal of killing the Shikabane group that killed her family, the Seven Stars.
Keisei tries to keep his brother Ouri away from the dangerous world of Shikabanes, but ultimately fails. After Ouri learns the truth about his brother, Keisei either has to quit being a contractor monk or kill Ouri because monks aren't allowed to tell anyone about the work they do. After Keisei saves Ouri from the traitor monk, Akasha, the Kougon Sect allow Keisei to still be Makina's contracted monk.
One night a member of the group Seven Stars possess Ouri and makes him stab Keisei. Though badly wounded, he's doesn't die. Keisei then expels the Shikabane from Ouri. Ashaka then attacks Keisei and injures him even more. Keisei still fights back and gets rid of Akasha and the Shikabane that were attacking Ouri and Makina. Knowing he's going to die, Keisei transfers
Injured Keisei with Makina
Makina's contract over to Ouri. If a monk dies before their Shikabane Hime, the Shikabane Hime could turn into a regular Shikabane. Keisei's final wish is to see Makina smile. Makina obliges, thinking Keisei might come back as a Shikabane if he is left with that final regret.