most terrifying fictional creatures I know?- quickright

the most terrifying and evil creature That I know is the chaos space marines from warhammer 40k because they move from planet to planet killing everything in sight because they want to and they don't have feelings and they don't have remorse. They once were mighty space marines but later in the conflict these space marine groups heard the whispers of the dark and evil gods of death and they promised wealth, fame and being free of the curse of following the other loyal space marines so the chaos space marines then worshiped these dark gods and so their super human bodies were mutated to horrible half humans and half creature. They do follow orders but only from their dark gods or their champions. Their are four gods of chaos Slaanesh god of charm, Khorn god of rage, tzeench god of wisdom, and Nurgle god of rot and decay. These four split the chaos space marine factions to where they wish for them to be...