The Type-05/F2Z Gekka S.E.I.T.E.N. is a 9th Generation Knightmare Frame used by the Novus Empire of Briton in the FanFiction, Code Geass R2: Twin Demons . It is piloted by Rio Shuska.
The Gekka S.E.I.T.E.N. looks like the original Gekka Pre-Production type, however it has parts used for the Guren S.E.I.T.E.N. The similarities between the Guren and this incarnation of the Gekka are the arms, shoulder armor, slash harkens, and wings. However, the body armor looks more like the Gekka's aside from the green gem that comes from the Guren. The main similarity between itself and the original Gekka is the blue color scheme. The Energy wings are a dark blue color.
The Gekka S.E.I.T.E.N. was created as a sister unit to the Guren S.E.I.T.E.N. It was planned by Rackshata Chawla when the Guren was returned by Kallen during the Final Battle for Tokyo. Only the specs were created and they were stolen by Nex, secretly Luis vi Britannia, when he escaped from the Ikaruga posing as Zero. Using these specs, he had it manufactured for Rio Shuska, the ace of the White Knight squadron. It made it's debut during Stage 24 alongside the Lancelot C.L.U.B.