First you need to lead a reaper queen into a trap (place foundations on the floor if you’re planning on getting multiple). Once it is in the trap close the gate so it can’t escape. Then start hitting it with a rock drake or something that can survive the radiation zone. You should have your glow pet on so you can deal extra damage. Once the reaper starts bleeding heavily, turn off your glowpet and wait 10 seconds before attacking again. Once you’ve hit a few more times it will have a pink aura around it, this means it’s ready to impregnate. Move your rock drake somewhere out of the reapers attack range. Once you’ve moved your drake you need to get close to the reaper avoiding its tail swipe. After 1 or 2 tail swipes you need to stand in front of it and it will go on all fours and pick you up in its tail and impregnate you. Once you’re impregnated turn your glowpet back on (to keep nameless away) and go to a birthing room. The reaper wont bury if you used foundations.
If you want your very own Reaper King, Here's what you'll need to do:
-Hunt down a Reaper Queen and get it's heath to below 2000. The easiest way to do his is a trap. When the Queen begins to grow red, it means she's willing to transfer a symbiote to you. Aproach her, and a cutscene will play. After the cutscene has ended, you'll have an Offspring Buff with a countdown timer.
- You now have until the countdown ends to gather as much co as possible. The amount if co you gain determines what level your Reaper King will be.
-Make sure to stock up on Pheromone Glands! You'll need them to truck the baby into thinking you're its mother. If you don't have any, it will attack you.
-Once the baby is born, is will run around, VERY quickly. It won't stop until it kills something. I would suggest building a small room (2×2 maybe?) and to have something for the reaper o kill. Make sure to consume the Pheromone Gland before the baby is born.
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.