The MSN-001X Gundam Delta Kai (aka δ Kai or δΧ) is a prototype transformable mobile suit developed from the MSN-001A1 Delta Plus. It appears in the Mobile Suit Gundam Unicorn video game, Mobile Suit Gundam U.C. 0094: Across the Sky and UC-MSV.

The final machine of Anaheim Electronics' Delta-type series, the Gundam Delta Kai is an enhanced version of the MSN-001A1 Delta Plus, which is used to demonstrate new experimental technologies that can be used for future mobile suits. As such, the unit is greatly overhauled from the regular Delta Plus, modifying both the MS and Waverider forms as well as enhancing its variable frame. Several thrusters were also fitted into the unit's legs and back skirt which allow the MS to fly in both space and under gravity, giving it a tremendous amount of speed and maneuverability. The Waverider mode can also function as a subflight system when needed.

Aside from the aesthetic change, the Delta Kai is fitted with various experimental weaponry derived from older mobile suits. This gives it a higher attack power and versatility than the Delta Plus, however despite the amount of weapons equipped it is very complicated to use in a tactical situation. The Delta Kai is also equipped with a specialized system called the n_i_t_r_o System, allowing regular pilots to gain Cyber Newtype-like abilities.