Worst Hero And Villain War Ever
The Gatekeeper was the spawn of an unnamed Elder God, his mother was an Outworld citizen who raised him early on to be a future Elder God, or at least a Demigod. Instead of choosing to serve the Elder Gods, The Gatekeeper instead started worshipping the dark Elder God Shinnok, the ruler of Netherrealm. At 16 years old, he sacrificed his own mother to boost Shinnok's power. This drew the ire of Elder Gods, who didn't want any children of Elder Gods to turn in the side of their mortal enemy. The Gatekeeper was banished into the recently created Earthrealm. He ended up becoming the being in charge of guarding souls between reality and afterlife.
His dark origins gave him power over mysterious realm known as The Black Hole, also known as The Penal Zone by some, and The Void by others. This dark realm was served for the very worst of universe's criminals, like a smaller version of Netherrealm. He also developed a fondness for playing games, and he liked to play with many Underworld citizens, promising them the possibility of living again if they win. The Gatekeeper was disliked for being very mischievous and often toyed with some of the badly-behaving souls with his games, but he never misused the dark power of The Black Hole.
Still, The Gatekeeper was removed from his position as the guardian of the Underworld, requested by Raiden supposedly, and instead was hired by Malmoth to be the guardian of Hell. The Gatekeeper kept playing the same games with the citizens of Hell, this time being a lot more unfair and abusive, for he knew that these beings definetly didn't deserve to live again. One being however managed to beat The Gatekeeper several times, the monstrous pirate known as LeChuck. The Gatekeeper is a very loyal subject to Malmoth, but also acts as his advisor.
Releasing The Demons
As the cogs of Ragnarok are set into motion, Malmoth asks The Gatekeeper to release two very powerful demons, LeChuck and Pyron, to roam the Universe again to cause destruction. The Gatekeeper warns Malmoth that the two beings are corrupted enough to kill Malmoth himself. Malmoth doesn't care and embraces the release of two demons instead.