It was originally a pretty terrible Chinese mod, but an anon from /jp/ started working on it and made it into something actually halfway decent, which spurred some other /jp/ anons into helping out too. The original anon apparently had another anon partner working with him too, but he disappeared so progress on the original mod stalled.
After some time, the one anon that was still working on it came into contact with the original Chinese devs, and helped reboot it into Tinder, which was basically a completely overhauled version of the original mod. Now he's helping them out with the Bannerlord version of the mod.
I still remember the very first threads where anon was posting his Warband stories and showing off the mod, time sure flies. It was noteworthy to me because I played the original mod back before then and it was pretty bad, they really turned it into something fun. /jp/ anons can do some cool stuff sometimes.