you need to kill an Alpha Reaper King to unlock the engram (get pregnant by a reaper queen, no matter what lvl and raise the baby) after unlocking the engram check the inventory of the reaper king you have to craft the item to evolve it. after the item is crafted just press E to let the Reaper consume it. will spawn a tamed Alpha Reaper King Max LVL + the Tame bonus ex: 600 lvl cap, the Alpha Reaper King will spawn lvl900. gl hf

thx :)

In aberration, any tips as to where I mgiht find a alpha reaper king??

i dont know, sorry :c good luck :)

try the surface, like vanilla alpha RKs