In M.U.G.E.N terms, a "slot" is a selectable character portrait on your roster. The Mercenary Screenpack is advertised to support (usually 10 rows of 40 or 8 rows of 50).
If you just want it to work right now without debugging every character: KOF Theory Mercenary Screenpack 400 Slots Down...
: Several iterations exist, including the Theory Mercenary V2 , which was collaborative work involving creators like Original Red F. and Tracy, often packaged with exclusive stages and music. Why It’s Recommended and Tracy, often packaged with exclusive stages and music
"Link is dead." "File not found." "The 400-slot version is down." If the Mercenary screenpack continues to let you
M.U.G.E.N 1.0 and 1.1 handle select screen arrays differently. If your select.def file has 400 lines but one single line is formatted wrong (e.g., kfm, stages/kfm.def, music=soundtrack.mp3 vs kfm, stages/kfm.def, order=1 ), the entire grid breaks.
If the Mercenary screenpack continues to let you down, consider these stable 400+ slot options: