Don Onitaijin (Japanese ドンオニタイジン; full combat name "Dai Gattai Don Onitaijin" / 大合体 ドンオニタイジン) is the central main mecha of the Donbrothers team from the 46th Super Sentai series "Avataro Sentai Donbrothers" (2022). The show adapts the Japanese folktale Momotaro: leader Don Momotaro (the "Peach Boy") and his four companions Saru (monkey), Kiji (pheasant), Inu (dog) and Oni (ogre/demon). The name combines Oni (鬼, demon), Taiji (退治, "to vanquish/exorcise") and Jin (神). Because Donbrothers was never localized for Power Rangers, neither the mecha itself nor this edition ever appeared as a Power Rangers toy — both are Japan-exclusive.

Don Onitaijin is formed as a grand combination (Dai Gattai) of the five "Robotaro" robot forms of the team members. Don Robotaro (Momotaro-based) is the core, forming the head, torso and upper legs and is piloted mainly by Don Momotaro; Saru Brother Robotaro (gorilla) forms the arms and chest plate, Kiji Brother Robotaro (pheasant) provides the shoulder armor and the Kiji Swords, Inu Brother Robotaro (dog) forms the left lower leg, and the Oni Robotaro form (demon) the right lower leg. The robot is armed with the twin Kiji Swords. Its signature and deliberately absurd design trait, emblematic of the series, is that the faces of all the participating warriors sit on the body all facing forward — the "robot where everyone looks at you." In the series, Don Onitaijin can also scale between human size and full mecha size.

The standard DX Don Onitaijin was released in 2022 by Bandai (Japan) as a fully transformable and combinable plastic model. This "Gold Mekki Ver." (full title 豪華観賞用 ゴールドンメッキ ドンオニタイジン, roughly "Deluxe Display Gold-Plated Don Onitaijin"; the "Gold-Don" wordplay puns on Gold and Don) is a special edition commemorating the "Donbrothers Final Live Tour 2023," distributed as a Premium Bandai / BANDAI Official Toy Shop exclusive; it shipped on February 20, 2024. It uses the same tooling as the retail model but features full-body vacuum gold plating (mekki) with a clear-color topcoat, additional gold paint and clear parts. Important for collectors: it is expressly a display-only piece — transformation, combination and articulation are not recommended by Bandai, as the coating can crack. Materials: ABS, PC, PVC and POM (body), ABS (swords). Contents: main figure, two sword parts and an instruction sheet.