Awkward relationship between high-school boys, Sunohara and Shinomiya.

From Momocha Scans:

Stephen and Shukurei are vampires who met and decided to travel together. One a half-demon, the other a subspecies. One lives for the sake of atonement, the other for the sake of revenge. In the midst of the journey, Steph drinks Shuku's blood and experiences once more the warmth of companionship. But when they arrive at Steph's hometown, the past begins to catch up, torturing Steph with sorrow and contrition. Shuku's father, whom they meet during the journey, reveals a startling fact, and Shuku intends to fulfil Steph's unexpected wish. What will they find at the end of their journey...?