Lupin Kaiser (Japanese: 怪盗合体 ルパンカイザー, "Kaitou Gattai Lupin Kaiser," roughly "Phantom Thief Combination Lupin Kaiser") is the main mecha of the thief side in Kaitou Sentai Lupinranger VS Keisatsu Sentai Patranger (2018–2019). It belongs to the three Lupinrangers — Lupin Red, Lupin Blue and Lupin Yellow — the season's phantom-thief team. A cataloguing note: the prefix "Kyutama Gattai" recorded here actually comes from a different series, Uchu Sentai Kyuranger; this robot's correct combination name is "Kaitou Gattai" (怪盗合体, "Phantom Thief Combination"). Because this Super Sentai season was never adapted into a Power Rangers series (Hasbro's subsequent Beast Morphers drew on Go-Busters instead), Lupin Kaiser was never released as a Power Rangers toy — it is a Japan-exclusive product.

Lupin Kaiser is formed from three color-coded "Dial Fighters" (red, blue, yellow) together with GoodStriker. GoodStriker becomes the lower body and legs, the Red Dial Fighter forms the chest and torso, and the Blue and Yellow Dial Fighters become the arms; the head is revealed through a dial gimmick — turning a safe-style dial on the upper section — echoing the phantom thieves' safecracking motif. GoodStriker itself is a highlight: a sentient VS Vehicle from the Lupin Collection that can side with either team, combining with the Lupinrangers' Dial Fighters to make Lupin Kaiser or with the Patrangers' Trigger Machines to make PatKaiser. The modular VS Vehicle system also allows alternate builds, such as swapping the Victory Striker in for the Red Dial Fighter to form Victory Lupin Kaiser.

The DX toy was released in 2018 by Bandai Japan as part of the "VS Vehicle Series" (DX Lupin Kaiser / Kaitou Gattai DX Lupin Kaiser). The set contains the three Dial Fighters and GoodStriker; it was additionally offered as a five-box configuration (one box per Dial Fighter, two for GoodStriker). Combination and transformation are done by hand, and the figure is predominantly ABS/PVC plastic — significant die-cast metal content is not a feature of this DX line. As part of the modular VS Vehicle assortment it is compatible with other pieces in the range (including the X Trains and Victory Striker) and serves as the basis for larger combinations up to Good Cool Kaiser VSX. No Hasbro or Power Rangers counterpart exists.