It's not possible, as far as I know, to add characters into the game (not replacing anyone) unless you're using Phantomwings' BrawlEx or custom made modules like the ones Dantarion made specifically for P:M.
This is correct. Incidentally, this was the wrong board to ask this my friend..The CSS tool CAN add new ID's to the code, but there isn't a point in doing it unless your using the clone engine. especially since the game will freeze if you hover over the blank icon.
anywho, a mod should really move this...