okay i tried taming this pet Battle-Scarred Runed Worg i had my settings set to mythic and it said was not tamable.
if you’re talking about fenrir in halls of valor, you need to kill him as a boss & then a tameable version spawns behind him in the cave.
After a quick search, I understand you are talking about Fenryr.
How it works is that you actually have to defeat the boss, then it will spawn in the cave and that’s the one you can tame.