Id like to mention that
Blackrock Battle Worgs phase out after completing a certain quest in the quest chain involving Keeshan. I do not know what quest causes it, theres so many from that chain that i think might cause it but i didnt realize they phased out so i didnt check it out after each stage to see when they finally vanish.
Apparently there is still some way to tame them out of phase but i can confirm that they only phase out if your in Alther's Mill. Its definitely possible to send a pet in and aggro them and then have them attack you from there... but a massive swarm of them comes after you so high levels for the armor value are definitely needed unless you have someone there to kill the excess wolves for you.
I can also say that if you aggro, you can waltz into the mill and they'll vanish and you'll leave combat so if your dying, you'll definitely survive if the lag monster doesnt get you.