Determined to kill his former leader for betraying their clan 3,000 years ago, Fraudrin takes on a newly resurrected darker, more powerful Meliodas. With Camelot now the stronghold of the Ten Commandments, the Seven Deadly Sins assemble once more to liberate all of Britannia from the Demon Clan. See Gowther's entry in the Seven Deadly Sins, for tropes related to the doll Gowther as a member of said group. Founder of the Kingdom: The very first Fairy King.
With the revelations of his true identity, this makes more sense: Estarossa has no 'powers of darkness' because he.