Megaton Musashi

In an effort to protect mankind and hopefully turn the tide of war against the Dracters to their favor, the united world government have built armored bipedal machines known as "Rogues" to protect the heavily-fortified shelters made to house the last of humanity. Designed to be mass-produced and deployed in large numbers, the Rogues, while less durable, are capable of taking enough punishment before breaking down. Nowadays, the regular Rogues are used as cannon-fodder for their more advanced successors.

Sometime later, development on a series of next-generation Rogues aboard the Shelter Ixia was reportedly finished and was later dubbed "Megaton-Class Rogues". These Megaton-Class Rogues are made from a special type of metal called "Megatonium", which was said to be stronger than any known metal ever known to man, making these type of Rogues more powerful and durable.

Musashi

The titular mecha of the series, named after Miyamoto Musashi, primarily piloted by Yamato Ichidaiji, though Terui and Ryugo occasionally operate the Rogue prior to getting the Sparkman and the Gaudia. Being the "jack-of-all-traits" amongst Megaton-Class Rogues, Musashi uses its twin swords to cleave through numerous enemies with relative ease, as well as firing a powerful beam from the Diffusion Cannon in its torso, obliterating anything unlucky enough to be caught in the blast. Unlike most Rogues, the Musashi has three separate components, the Upper Torso, the Arms and the Lower Torso, which must be assembled together on higher altitudes via the Sky Build (スカイビルド, Sukaibirudo) formation.

Arthur

Inspired by the heroics of legendary King Arthur, this Megaton-Class Rogue excels in close-quarters combat using its sword, as well as possessing a centaur-like lower body, enabling greater mobility and agility amongst other Megaton-Class Rogues. Primarily piloted by Reiji Amemiya.

Maximus

The range-focused fighter amongst the Megaton-Class Rogue, the Maximus utilizes the many missile pods in its body to fire an endless salvo of heat-seeking missiles to wipe out multiple targets at once. Inspired by the Pontifex maximus. Primarily piloted by Jun Kirishima, with Momoka Saotome serving as the co-pilot.

Sparkman

Inspired by Thomas Edison, the Sparkman is able to make use of the electricity it constantly generates, either to augment the destructive potential of whatever weapon the Rogue is holding, or by harnessing its raw power to amplify its attacks through a variety of ways. Primarily piloted by Teru Asami.

Gaudia

The physically strongest out of all the Megaton-Class Rogues. Inspired by the brave warriors of ancient Rome, it utilizes the raw strength to crush its oppositions through sheer might alone, as well as using its large body to shrug off any blunt hits. Primarily piloted by Ryugo Hijikata.

The project was originally announced on July 27, 2016, and set to begin in Q3 2017.[5] Developed and published by Level-5 and directed by Akihiro Hino, the game released in Japan on November 11, 2021, for the Nintendo Switch and PlayStation 4.[6] Following the game's release, it has received free updates with additional content. Paid downloadable content (DLC) was released throughout 2022.[7]

As of March 2023, the game has included collaboration with various anime robot properties including Mazinger Z, UFO Robot Grendizer, Getter Robo, Combattler V, and Voltes V.[3] On September 20, 2023, an English trailer was publicly released.[8]

The anime television series for the franchise was announced along with the game.[5] The series was produced by OLM and directed by Akihiro Hino (chief) and Shigeharu Takahashi, with scripts also written by Hino, character designs by Takuzō Nagano,[9] and music composed by Ken'ichirō Saigō.[10] The series aired on Tokyo MX and BS Fuji from October 1 to December 24, 2021.[4][11] The series' theme song is "Musashi", performed by Zuma.[12]

The second season aired from October 7, 2022, to March 17, 2023.[13] The theme song is "Eiyū no Uta", performed by Kodai Matsūra.[14]

Several episodes were delayed,[15][16] with episodes 24 to 26 airing from February 3–17, 2023, and the remaining two episodes airing on March 10–17.[17][18]