Nil-cross

A Nil-cross is a T-Spin Triple stacked on top of an Imperial Cross. The terrain pattern which could be transformed into this setup is a bit hard to detect. Although it is hard to detect midgame, this setup could be derived from a few openers.

Midgame Setup
The easiest way to detect this setup derivation is when it creates an Imperial Cross shape with one of the sides of it has a single pointy piece right next to the kick hole. For the aforementioned terrain, instead of directly going for an Imperial Cross, player could deny the overhang and create a Nil-cross for more firepower. Please do note that stacking a Nil-cross would make the user vulnerable towards enemy's spike due to its height.

Derivations
After the T-Spin Double, it can be continued with a T-Spin Triple, Imperial Cross or if the Nil-cross is at the left or right side, Infinite TST.

The above field can be continued with Infinite TST instead.

In case of the first diagram, it can be continued with a T-Spin Triple or Imperial Cross.

Opener Derivations
As mentioned above, a few openers have continuations towards this setup.

Gamushiro Stacking
A Nil-cross could be made as a continuation of Gamushiro Stacking right after the initial T-Spin Triple.

HeboMAI Spin
HeboMAI Spin is an opener occasionally used by Japanese player HeboMAI during his time playing Tetris DS. It starts with a T-Spin Mini Single (which was used to be recognized as a T-Spin Single in the game). This could continue to a Nil-cross.