Can't kill Tartarith, Tenebris is not with me

So when I went to fight Tartarith, I fought him for about 10 minutes. Tenebris wasn’t doing anything, so I ran. I went back to fight him, no NPC’s on the floor for the quest, and Tartarith just says “Time to die again” and then I fight him to no end. Tenebris just seems to be bugged out or broken or something. Unless I’m missing an item or something, because I can’t go back to Tenebris’ realm. Thank you for any help in advance.

edit I restarted the game and it fixed everything.