SF4 Koryu is a mod made by the developers of Remix, years before they began work on Remix. It is a total overhaul mod similar to Remix, but is generally much sillier and less balanced, and most system mechanics in Remix aren't present. Koryu characters come bundled with installations of Remix and can be selected with version select, but are banned from all tournaments due to not being well balanced or thought out. As such, they only see play in novelty brackets or casuals between consenting parties. We do not plan to cover Koryu characters on this wiki at the moment; if you have any questions about them feel free to ask in the Remix discord.