If you want to tame it I am 100% sure that 2 rock drackes can finish it of too 1k HP whistle your rock drackes too passive then grind exp for the reaper and kill some reaper to get someshard when you are ten seconds early wait till ten seconds then consume the shard after consuming it a cyropod will appear on your invetory than cyropod it out and BOOB KAHA PHEW PHEW!!!!You got a reaper imprint it and 9ther bla bla stuff you got a fully grown reaper king
In order to get a reaper king, you must find a queen, found in Halls of the Reaper Queen, then you must hit it
via Rock Drake or ballista turrets until it has a reddish pinkish glow, then walk up to it with good armor and a couple shields, it will then sniff you and grab you with it's tail, when it is done grabbing you, you will be severely injured, you have 5 hours to grind xp for the queen, kill other queens for pheremone glands, and when the time comes, on the last ten seconds, eat a pheromone gland and have a cryo on you in a pen, claim it, and cryo it, when deployed, it will act normal. Now you raise it, and bam, you have a reaper.
To obtain a reaper king you must first find a reaper queen which you must then lower their health to almost dead after you have done this you will have to tank its hits for a while whilst you wait for it to impregnate you once it does this it will bury back underground leaving you at severely low health, at this point you should return to your base where you should have reaper pheramone glands which are obtained by killing reapers however whilst you wait you can gain experience by killing things which will increase the level of your reaper king after it burst, after the 12 hour long wait from first being impregnated is over you should consume a pheramone gland which will alow you to imprint to the baby after it has burst out of you withought killing you, after you have imprinted on it you just raise it much like any other meat eater feeding it raw meat until it matures however if you would like to aquire multiples of these creature you will have to repeat the process ovee again.