Until the Full Moon

"ridiculous!! I'm not going to let 100 or 200 year old kids go decide what's best!!"

—Arnet Vincent

Marlo: You may not believe this, but when I bask under the full moon I turn into a woman. I'm descended from a werewolf clan that transforms on the full moon.

Louis: You're right. I don't believe you.

—Chapter 5

A two-volume manga by Sanami Matoh, creator of FAKE.

Marlo has a problem. On the night of the full moon, he turns into a woman thanks to a recessive genetic quirk brought out by his half-vampire heritage. Desperate for a cure, his parents return to Europe to pay a visit to Doctor Arnet Vincent, a family friend and the best physician in the vampire world. Marlo tries to keep his condition a secret from the vampire playboy David, his childhood friend and Arnet's only son.

He fails, and when Arnet declares that he is unable to cure Marlo, the parents decide that the next best solution is marriage -- between David and Marlo. Hilarity Ensues.

Subsequent chapters mostly follow the adventures of the couple as Marlo comes to terms with the meaning of his transformation.

Tropes used in Until the Full Moon include:

Arranged Marriage
Bishonen- Marlo (male), Vincent, Arnet (younger), Georgio (younger and older), Erik, Kyle and Louis.
Casanova- Before Marlo's return, David is reputed to be this, and it shows.
- After his engagement to Marlo he becomes more of a Chick Magnet, as he doesn't actively encourage women to fall for him, they just do.
  - Or else he just isn't shown encouraging them.
Clingy Jealous Girl- Ira, Marlo's ex-girlfriend from the United States.
Deadpan Snarker- Louis manages at least traces of this in all of his appearances.
- David himself, on occasion.
Defeat Equals Friendship- Just about every chapter. Someone tries to get between Marlo and David, gets beaten, and is subsequently invited to the wedding.
Ho Yay
- And how!
Medium Awareness- Marlo occasionally makes offhand remarks about how they're in a shoujo manga.
Naked First Impression- Marlo's first meeting with Belicia.
Not Blood Siblings- David's old friends Belicia and Erik, who happen to be in love with each other.
Our Werewolves Are Different- Instead of turning into a wolf, Marlo turns into a woman.
The Power of Love- The reason Marlo can turn into a girl.
Tsundere- Marlo is often a Type A toward David, but it's all for show.