The achievement Family Familiar
is the largest and toughest addition to the pet battling world in a long time. It might even beat the Celestial Tournament in required effort!
To complete it you need to earn 10 individual achievements, each asking you to defeat 12 tamers in the Broken Isles with only pets from one specific pet family.
But how hard can it be? Well, you're in for quite a ride. Every day there is only three active pet quests out of a total of 37 different ones.
So first off, one of the tamers in question has to be active.
Then you need to beat him or her, not once, but several times with teams using each specific pet family.
Once you complete the achievement, you will get your very own tiny, corrupted, adorable Nightmare Treant