Kaiyorihito Kaiyorishiki

It is said if you collect all the "aya", you will receive great power.
Aritsune is a smart, athletic high school student that lives a happy life together with his sister, Akira, and his friend, Chihiro. Aritsune is also the head of the Sagimori House and holds the powerful "Kaiyori no Aya," which makes him a target of rival houses. Occasionally, Aritsune receives orders from his house to deal with rouge collectors of aya who hold no regard for others in their quest for power. Chihiro fights alongside Aritsune and helps him control his power. Their peaceful school life is coming to an end with the rise of violent crimes and arrival of suspicious transfer students. Who can Aritsune trust?
(Source: shinkeikaku)
Note: Discontinued by publisher due to copyright infringements.