Similar to Meldo is doing with mediafire links with mega, I've been backing up mugen characters to internet archive. Since it is wise to have more than one backup on hand. Internet archive does include bittorrenting if your internet speed is slow. Sending links to characters to me is more than welcome, this doesn't have to exclusive to characters that are on mediafire.
Spoiler: Individual Author Links (click to see content)
Spoiler: Full Games (click to see content)
All of what I've backed up in whole: https://archive.org/details/@amidweiz