Jason Goes to Hell is a sequel that brings something new to the franchise by having Jason destroyed at the beginning but he still lives through his heart and after making a coroner eat it he posses him and continues killing people until he finds a new host to put his heart in.
But these bodies cannot work for long, if something happens to them he needs a new host but the only way he can have his original body is if he finds a blood relative a transfer his heart into her.
The blood relative also has the power to stop Jason with a dagger that once impaled in his immortal heart will send him to hell and the bounty hunter knows that.
So Steve and Jessica confront Jason and after cutting the bodies head open Jason's heart that has sprouted a head, arms and tail crawls out and is thrown into the basement where he finds the body of his sister that he killed earlier on. After going into her the Bounty hunter tells them that he doesn't have to be reborn through a living Vorhees woman.
And so Jason is in his same body again and while fighting Steve Jessica impales the dagger into Jason sending him into hell.
And has Jessica and Steve and their little daughter walk off Freddy Kruger's hand comes out the ground and pulls Jason's mask into the ground, this inspired the Freddy Vs Jason idea.
Although Jason is not in it much the idea of telling us what makes Jason immortal and how to kill him was quite good. 10/10