Tenbin wa Hana to Asobu

is a japanese manga series written by Unohana Tsukasa. It began serialisation in the November 2008 issue of Manga Time Kirara Forward.

The series was released under 2 volumes from April 2009 to October 2009.

Synopsis
Lotus Girls' Academy. A school whose aim is to educate young girls to be pure and modest. Youko is a new transfer student here, and immediately takes a liking to Shuu, who shows her around the school. However, Youko discovers a big secret about Shuu... she's a vampire! Youko then does her best to be the best friend she can be and help Shuu protect her secret... whether Shuu likes it or not! But how does Shuu really feel about Youko... and why does her blood taste so different? And to what lengths will Youko go to help Shuu?

(Source: MU)