HALO is rerulili's fourth album. It contains 8 tracks, sung by Hatsune Miku, GUMI, and rerulili. Also featured are guest musicians [TEST] and Yuumao, and guest vocals by Gero. It was first released at Comic Market 82.
A crossfade of the album can be heard on Nico Nico Douga.
The album is purchasable on Toranoana.