regret is Mai Hoshimura's 13th single released under SMEJ label. It was released on June 4, 2008. The title track was used as the 7th ending theme for the anime series D.Gray-man

D.Gray-man

is an ongoing Japanese manga series written and illustrated by Katsura Hoshino. The series tells the story of a boy named Allen Walker, a member of an organization of Exorcists who makes use of an ancient substance called Innocence to combat the Millennium Earl and his demonic army of akuma...

. The single peaked at #30 and charted for 4 weeks in the Oricon charts selling 3,465 units on its first week. The coupling Sakura Biyori x Oshio Kotaro is an acoustic version of her previous-released song, Sakura Biyori.

This single's catalog number is SECL-643.

Track listing

1. "regret"

   Composition/Lyrics: Mai Hoshimura

   Arrangement: Suzuki Daichi Hideyuki

2. "Love Tuning"

   Composition/Lyrics: Mai Hoshimura

   Arrangement: Shiraishi Satori

3. "Sakura Biyori x Oshio Kotaro"

   Composition/Lyrics: Mai Hoshimura

   Arrangement: Oshio Kotaro

4. "regret (D.Gray-man Ending ver.)"
5. "regret" (instrumental)

Charts and sales

Oricon Ranking (Weekly)	Sales
30	6,313