"修羅ノ庭 ver.LEN -Garden of berserker-" is Wonderful☆Opportunity's singles album; based on the song of the same name. "修羅ノ庭" was at first a Rin original song by Minus-P; however Len's version was more prefered. It was later licensed by Karen-T as a singles album which consist of the cover by Len, and also the off vocal by Len and Rin (version).

The singles album Garden of berserker is available for purchase in iTunes store

Garden of berserker
Released February 8th 2011
Producer Wonderful☆Opportunity
Price ¥300
Illust. -
Label Karen-T
Track list
1. 修羅ノ庭 ver.LEN -Garden of berserker-
Shura no Niwa ver.LEN -Garden of berserker-
Kagamine Len
2. 修羅ノ庭 ver.LEN -Garden of berserker- (off vocal)
Shura no Niwa ver.LEN -Garden of berserker- (off vocal)
3. 修羅ノ庭 (off vocal)/ マイナスP
Shura no Niwa(off vocal)/ Minus-P