Vampire Dormitory 9

Ruzé, the long-lost twin brother of Ruka, has fallen hard for Mito, and attacks Ruka to steal her for himself! But Komori, the Progenitor of the Vampires, blocks his attack…and the only way to heal his wounds is with the magic of the Vampire Lord's crown. To unlock the crown, Mito must marry Ruka—and if she does, she'll become a vampire herself, forever banished from the human world! But when Juri asks her to abandon the Land of Vampires and help him rescue Takara instead, will she be able to choose love over friendship?!

Volume 9 of the Vampire Dormitory manga series by Ema Toyama.