KING & KNIGHT (Wonderful☆Opportunity BEST KING & KNIGHT) is Wonderful☆Opportunity's eight album (their first "BEST" album; labeled "volume one"), the previous being Wan☆Pero！; featuring Kagamine Rin and Kagamine Len. This album was first released on VOC@M@S 21 on July 8th.
It consist of 26 tracks, divided into two CDs "KING WHITE" (Jesus-P BEST) and "KNIGHT BLACK" (Minus-P BEST). 24 of the songs are fully remastered with the Kagamine's Appends and V3s. It also includes a 28 pages booklet, a paper bag, postcards, done by various illustrators such as Zashiki Usagi-P, Anom, Glider, and several more.