Itsudatte My Santa!

Itsudatte My Santa! (いつだってMyサンタ!, lit. "Always My Santa!") is a manga by Ken Akamatsu. Originally a one-chapter production, it ran in Japan before Akamatsu's Love Hina was serialized. It ran in Shōnen Magazine in 1998, and was serialized in volumes 4 and 5. An anime OVA, with two episodes, was released on December 7, 2005 in Japan. The anime OVA was licensed in the United States by FUNimation.

Plot
In the story, a girl called Mai appears before a boy who happens to hate Christmas. As it turns out he was born on December 24 and thus was named Santa, causing him to hate the holiday. Moreover, as a child, he never had any festive occasions, such as birthday parties. With the power of Christmas, Mai is given the mission to improve his luck and change his views for the better.