Black Onitaijin Murasame (Japanese ブラックオニタイジンムラサメ, Burakku Onitaijin Murasame) is a giant mecha from the Super Sentai series "Avataro Sentai Donbrothers" (2022–2023). It does not belong to the core Donbrothers team but to the lone dark warrior Don Murasame (ドンムラサメ) – a weapon-like combat entity created by the Nōto ("Brain People") as a countermeasure. It is the black counterpart to Don Onitaijin, the main mecha of the hero Don Momotaro. Within the show, Black Onitaijin Murasame was rendered entirely in CGI (no physical suit was built); its design is essentially a blacked-out Don Onitaijin with an altered chest plate, a modified helmet and its own swords.

Like its template, the robot is formed by combining five black Robotaro units: Black Robotaro serves as the central body (from Don Murasame's transitional form) and joins with Black Saru, Black Oni, Black Inu and Black Kiji Robotaro to complete the mecha. It is armed with a pair of "Sawshark Swords" – sawshark-themed barbed broadswords that Murasame can wield remotely via telepathy. An enhanced "Future" form (Don Murasame Future) also exists, built on the same mecha.

The DX toy was released in 2023 by Bandai (Japan) as a Premium Bandai exclusive and is a black repaint of the 2022 DX Don Onitaijin. It is made primarily of plastic (ABS/PVC), is fully articulated, stands roughly 36 cm tall, and assembles from five separately combinable Robotaro units. This variant features metallic-style paint, the two Sawshark Swords as accessories, and optional swap-in hand parts that allow display in both the standard Murasame and the Future Murasame mode. Note for collectors: because "Donbrothers" never received a Power Rangers adaptation, this mecha was never released as a Power Rangers toy – it is Japan-exclusive. Aside from the DX model, only a separate Mini-Pla model kit (a build-it-yourself plastic kit) exists, which should not be confused with the pre-assembled DX item.