The Skulls (as they are called) are sub-bosses in the Konquest mode of Mortal Kombat: Armageddon. They are flaming phantom skulls that are also the type of Hellspawn demons. They are denizens of the Netherrealm.
To prevent the demigod Taven from advancing in his quest to stop Armageddon that is happening in his homeworld of Edenia, the ninja spectre Scorpion after his arrival in Edenia, sent the Skulls to face him, but they were defeated by Taven using projectiles via his powers since each Skull remained distant.
Non Playable Villains
Mortal Kombat Legacy