Call of the Night Vol. 3 (manga)
Nazuna isn't the only one who thinks Ko is a delicious snack. And Ko isn't the only one who gets jealous. When Ko draws the attention of four other vampire girls with nefarious intentions, he must fight for his life--even though he wants to give it up to become a vampire. But only to a certain special someone. Unfortunately, there's a time limit on being "turned," which raises the...uh...stakes. Then, Ko follows some dating advice that backfires. Undeterred, he tries to help another vampire and mortal mend their love/hate relationship.