The hive- like ancient creatures like parasites that go underground by digging and make tgeir colonies and since tgeyre parasites tgey try to infeect other living beings (not all only the ones compatible with the infection like humans cabal etc) . amd tgeyve been around before humanity!!! and the fith race or darkness-what if yu destroy it and it turns into a gas form tgat evaporates ibto space somewhere unkiwn (like a black hole) then after a couple years the gas form or farknes (black soul) takes a shape of a creture tgen comes back to earth!