Mamotte Shugogetten! (1998)

High school student Tasuke Shichiri receives interesting gifts from his parents, who are archaeologists travelling around the world. One day he receives a relic from China, said to bestow upon the pure of heart a guardian spirit to protect them. In Tasuke's hands, the relic releases Shaolin, a beautiful moon guardian sworn to obey and protect her master. But it's been four thousand years, and the world has changed since Shaolin's time, leading to many complications. To make matters worse, more guardians arrive at Tasuke's doorstep, and he must not only keep them from interfering with his life, but must sort out which guardian he truly wants to spend his life with.