If you’ve ever dreamed of pitting Kamen Rider Decade against Kamen Rider Geats, or having a battle royale between Shadow Moon and Ark-Zero, you’ve likely stumbled across the keyword "Download Mugen Kamen Rider." For over two decades, the 2D fighting game engine M.U.G.E.N (commonly styled as MUGEN) has been the wild west of fan-made fighting games. And within that universe, Kamen Rider is one of the most beloved and content-rich niches.