Sekiren (隻蓮) is a contract employee for Astral, an expert in Buddhism and also belonged to the first generation of Astral members.
He is usually seen in a komuso attire and has short, spiky hair and a scar, that runs from the top left of his forehead to his left cheek.
Sekiren has been practising Vajrayana since he was quite young and is additionally a genius martial artist and proficient weapons fighter.
Ever since the Larva incident, he has been training Itsuki in Martial Arts. He has an old-fashioned way of thinking, even trying to perform seppuku as a form of apology to Itsuki, as seen in an episode. Contrasting his abilities in battle magic, Sekiren possesses a peace-loving personality and is romantically interested in Goetia's Daphne. He is the Chief Priest of Ryuuren Temple though he is known to be a wanderer. He was known to be in charge of the meals for Astral during his time with Tsukasa and is a culinary expert with enough self-recipes to call his own. He loves sweet stuffs and is known to have travelled to a cafe and cake shop by train range and even made a gourmet map. Adilicia calls him "A Monk Who Breaks A Vow".
Among the members of Astral, he is most familiar with the Dark Magician's Society: Ophion. He finds those who would choose taboos to be repulsive, a belief he shares with Nekoyashiki. He is also one of the three people responsible for making Itsuki's eye patch. By request of The Association, he travels to Italy, Venice and encounters Fin, where a battle ensues.
After the Kyoto incident, Sekiren visits Itsuki to complete his training for the basis of the Five Elements Fists and leaves for Hong Kong with Itsuki after its completion. He then leaves Itsuki with Hazel and left for his journey of re-training. In the third part of the story, he leaves for England with Daphne to investigate The Silver Knights. He also revealed to Daphne that he was a close friend of her father, Oswald and related her father's words to her.