Kaitou Milky☆Drop(2006)

Kaitou Milky☆Drop

I, Miruku Mogi, while being a cafe waitress, I became a Mysterious Thief Milky Drop to become a "Pandora's Pupil" so that the curse on my brother could disappear. It was hard to find it. One day, I asked Nezumiya, Kozo Nezumi's descendant, to look for the treasure, but ...!?

(Source: Goodreads)