There are times when you get the quest to "defeat her pet and give her the flesh." Easy enough, right? - But wait! What if the mob limit prevents the "pet" from spawning? Then this Coven Witch is useless. At least for you, the one that got the quest. I've got this quest twice out of 7 Coven Witches, and both times, the "pet" didn't spawn. This makes it impossible to finish the quest. Now, I don't know what the "pet" is supposed to be, but I wonder if you could whitelist them, allowing them to override the mob limit. Coven Witches are hard to find, and when you get a task you can't finish, it's just annoying.
The pet is also a vanilla mob with increased health/stats. Why do you need so many coven witches? 6 is the most needed for any of the current content iirc
That's the thing, I have 5 (found 7, 2 of which didn't spawn their "pet") right now and it's going to be annoying for other people as well, that tries to get the 6. Coven witches aren't the most common entity to find. Quite rare.
