Birdy Cephon Altera  

Arita Shion, Birdy the Berserker Killer, バーディー・シフォン＝アルティラ

An Intergalactic Officer named Birdy appears human-like but is actually an alien. She's on Earth pursuing a criminal across interplanetary borders when she unintentionally takes the life of a young boy who was in the wrong place at the wrong time. As punishment, Birdy must share her body with his to save his life. This means she has to deal with Tsutomu and his family while still performing her duties.