The way this game works is that after you beat every other character (excluding yourself, as the game doesn't allow mirror matches), you will get the first part of the ending. You then have the task of beating everyone again, when this is done you will get the second part and finish the game. The guy who challenges Haggar at the end of the second part is Ortega, who is playable in the game's sequel, Ring of Destruction.

First Part
Second Part