Data is a kind of Magical Boy series manga by Tachibana Kaimu. The two main characters, Sakura and Yuki, are on quests to gather stones with magical powers. In doing so they are also hoping to uncover the mystery as to why they both seem to have lost their memory. Although this is a shoujo series, I'm pretty positive theres also something shounen-ai going on between the two (subtle but there.). A lot of new characters who are also "hosts" for the stones join in the fun as the story progresses.