We're ARKS! Readoro☆KOI☆KOI! (Japanese: We're ARKS! レアドロ☆KOI☆恋!) is a soundtrack featuring the two songs from the CD's title. Readoro KOI KOI, also known as Rare Drop KOI KOI, was originally introduced into the series as the episode ending theme of the anime series, Phantasy Star Online 2 The Animation. Also included are different mixes of each single, including karaoke and live performance versions.