Complex sentence: Mark deletes Ace's game file, which is supposed to return all three of them to the game, but because of Lady Illusion's intereference, only Ace and Sparx are sent back into the game, leaving Random and Lady Illusion stranded.
Split into simpler sentences: Mark deletes Ace's game file, which is supposed to return all three of them to the game. Because of Lady Illusion's intereference, only Ace and Sparx are sent back into the game, leaving Random and Lady Illusion stranded.