When I named the 2:2:1 leaper after a Japanese stealth warrior (or 'Nearly Invisible Nutter Jumping Around', as one Terry Pratchett fan calls them) all I had in mind was a pun on its SOLL of 9, extrapolating from the existing 2:1:1 Sexton's 6 and continued with my 3:1:1 Elf's 11. Little did I realise at the time how strong it was not just as a piece but as a concept. Where for a 2d oblique piece a pair of directions has one further pair of its directions at right angles, like standard (Bishop) diagonals, and for a typical cubic one it has none, like the nonstandard (Unicorn) diagonals, a pair of Ninja directions has two pairs, like orthogonals. Huge numbers of pieces with SOLLs divisible by 9 can therefore be expressed as two or three moves in Ninja directions, as all moves can from Wazir steps. Here is a table comparing cubic moves comprising Wazir steps, Trebuchet leaps, and Ninja leaps. Note how many pieces can be formed of the same combinations of Trebuchet and Ninja leaps. Note that cubic SOLLs include neither 7 nor 63. Note also that the Cassowary and Zhemois moves cannot be formed of Ninja ones at right angles because the zero coordinate cannot be achieved from a 6:6:3 leap and a 2:2:1 or 4:4:2 one as it can from the latter two.
[2:2:-1]+[2:-1:2] Nimel
[2:1:-2]+[2:-2:1]+[1:2:2] Exorcist
2[2:1:2]+[1:2:-2] Chipmunk
2[2:2:-1]+[2:-1:2]+[-1:2:2] Expounder
2[2:1:2]+[1:2:-2]+[2:-2:-1] Propounder
2:2:1 Ninja
6:6:3 Nhimois
2[1:2:2]+[2:1:-2]+[2:-2:1] Nhimois
2[2:2:-1]+2[2:-1:2]+[-1:2:2] Opossum
2[2:1:2]+2[1:2:-2]+[2:-2:1] Ultimatum
3[2:2:1]+[2:-1:-2] Hogger
3[2:2:-1]+[2:-1:2]+[-1:2:2] Loner
3[1:2:2]+[2:-2:1]+[2:1:-2] Whiner