Death and revenge make up the very core of Jason Voorhees' being. He died as a young boy. His mother killed out of grief and rage. When she was murdered, Jason returned and avenged her. Many times since, the living have tried to send him back to the realm of the dead. He's been stabbed, drowned, electrocuted, hurled into space. But Jason cannot be killed. Cannot be stopped.
Like Scorpion, Jason Voorhees was a revenant: a vengeful spirit returned to life.
Hundreds had fallen victim to his bloodlust.
Liu Kang, now ruler of the Netherrealm, took notice.
An immortal killer like Jason would be useful in his plans for konquest.
He drew Jason into the Netherrealm and offered him an endless bounty of slaughter...in return for his allegiance.
Jason's simple reply was to destroy Liu Kang.