It sounds more like he's saying "from the Talos realm" not "from the terrors realm". The "L" in "Talos" is a lot easier to make out than the "r" in "Terrors".
I looked it up and found this https://en.wikipedia.org/wiki/Talos_(Forgotten_Realms).
I'm thinking this is the main inspiration for a new dimension where the doom hunter comes from.
It could also be "Telos", but I didnt find much on it.
https://forgottenrealms.fandom.com/wiki/Telos
https://forgottenrealms.fandom.com/wiki/Telos_(city)