The X Emperor is the personal mecha of the sixth warrior, Noël Takao, from "Kaitou Sentai Lupinranger VS Keisatsu Sentai Patranger" (2018, the 42nd Super Sentai season). Noël holds a unique position in the series: he is simultaneously Lupin X (the silver member of the phantom-thief team, the Lupinrangers) and Patren X (the gold member of the police team, the Patrangers), making him the only warrior who belongs to both opposing teams. Fittingly, his mecha is train- and locomotive-themed, setting it apart from the vehicle designs of the Dial Fighters (Lupinrangers) and the Trigger Machines (Patrangers). Because this season was never adapted into Power Rangers, the X Emperor is Japan-exclusive and was never released as a Power Rangers toy.

The X Emperor is assembled from Noël's "X Trains" around a sentient core, X Train GoodCool, which serves as a counterpart to GoodStriker, the linking mecha shared by the two main teams. Its defining feature is a pair of combat configurations the pilot switches between: X Emperor Slash, armed with a sword for close combat, and X Emperor Gunner, fitted with a large cannon for ranged attacks. Beyond that, the X Emperor can also join with the standard robots LupinKaiser and PatKaiser to form larger combinations, acting as reinforcement for either team.

As a toy it was released as the "DX X Emperor" by Bandai Japan in 2018 as part of the VS Vehicle line. As is typical for this generation of Sentai mecha, it is made predominantly of plastic (ABS/PVC) with virtually no die-cast content. A single set reconfigures the train cars to build both robot modes (Slash and Gunner) and includes the X Train GoodCool core. It is compatible with the separately sold DX LupinKaiser and DX PatKaiser. Since Hasbro produced no adaptation of the season, there is no Power Rangers counterpart.