It's pretty easy to tame a bloodstalker. You just need a blood transitions set and suck out 400-700 blood packs, but be careful if you do that, you'll get 20 damage per pack. It's worth keeping some condensing salt in your inventory It's about 50 minutes then it's also good to take 10 parachutes with you because the bloodstalker could throw you down if you If you have all this you have to go to the moor in a place with giants and big trees hanging on the branches of the trees then sometimes the bloodstalkers when you see them they have already seen you now they will pull you towards them sometimes they will let you go for that the parachutes it can take a second for them to grab you again then once they have you they will automatically suck the blood packs in your inventory and you will automatically tame them