Make sure you have unlocked the level "Ancient Path Of Death" and select level 51-70. Also, make sure you have the gene command "Absolute Zero" -- simply use it in pairs and see that all your hits make a "BlowOUt"
Defeat the Almighty, then complete the game and save it. However, instead of starting a new game, load the saved game. Access and complete the new map and defeat the Almighty at the end. You can now select Ayuta and Mana as well as Olgar and Vhati by using the arrows at the bottom of the character selection screen.