are u hoping to get eternal pet from feat?
trust me. dont hope too much on that lol. currently i have 24-28 Eternal pet (dont remember well since some in other toon bag), if i remember correctly i only obtain 3-4 Eternal pet from enslaver feat, the rest from random drop.
what i do is just farm at low floor 100+ equip Eternalized (6) 300%+300% From treasured, just farm like hell. convert all eternal drop for high tier crystal while loot lower tier crystal from killing mobs. encounter enslaver, drop legend pet is bonus from farming. getting eternal is luck.
Note: Even with that amount eternal pet, I still dont have any with Flat HP and Flat ED in 1 pet lol. biggest RNG troll.