Well I killed paarthanax. Worse mistake ever. I would make another character but I have gotten so far with this one. I want to bring him back to life, is there any spells I can use? What is the best conjuration spell??

Dread Zombie.

You use Dead Thrall to bring Paarthurnax back.

Kidding. You can't revive a dead Dragon unless you reload a save prior to where you made your decision.

That really svcks. It was a while ago so I would lose a lot of things if I try and reload the save proir.