The first step to tame is to create a trap for the reaper so when they impregnate you you have a safe place to hide from all the predators. Then go with your tribe and a small charge light creature (bulbdog best, highest charge) and turn off the light and wait until you come across a reaper with the level you want to tame, then you and your tribe attack and bring it down to low health (careful not to kill) and allow the reaper to impregnate you and hide wait to birth but make you you have reaper glands or else you and your tribe with be killed by the little menace as it doesn’t follow commands and attacks everything