since he still possesses at least a significant amount of a Godhand's power even though he was supposedly reborn as a human, and seems to still be backed by the other four demon lords, he actually IS a Crystal Dragon Antichrist , who is currently posing as a Dark Messiah

And in a later arc, Griffith is called an actual Messiah by the people. He has the Crystal Dragon Jesus equivalent of the Pope proclaiming him to be the best thing since sliced bread

including the Band of the Hawks that he once led, whom he sacrificed in order to become Femto in the first place

setting himself up as the ultimate tyrant and concentrating the hatred of the world on him, so that when he's killed, the world can finally unite in peace

created an entire country where he rules as a relatively benevolent Emperor, though he himself admits he didn't create Albareth for the sake of being a ruler

twelve disciples in the form of the Spriggan Twelve

capture the limitless magic within his former lover Mavis and use it to time travel back to the past to stop himself from becoming immortal. To him, he views his existence as having brought untold calamity to the world in the various magic users looking for his artifacts, emulating him and so on. And he's unfortuantely quite right as most of the villains could be traced to him as their origin, with the main exception being ironically the most dangerous one, Achnologia. However, it would in fact destory the world in the sense that Natsu and everyone would not exist by changing the past.