Ruin Hunter Raichi

Ruin Hunter Raichi came out for PC in 2002.

Lychee, a girl who has lost her memory, and her companion, the mysterious young man 456 (Yogoroo), are traveling in search of the only clue they have left, the Ruins . One day, they learn of ruins where a witch named Habayaga is said to have lived, and arrive at Questar Island, where the ruins are located. What awaits them there...?