Eclipso

Before the Spectre became the wrath of God and the angel of vengeance, Eclipso was the one responsible for dispensing the divine justice. But he turned evil "“ when he is responsible for the Great Flood, turning evil afterwards is beyond any comprehension.

In any way, his spirit was locked inside a black diamond, called the Heart of Darkness, from where he could possess anyone with whom he came in contact. When displaying his full power, he demonstrated all the superpowers which make the Spectre the most powerful of DC superheroes. But Eclipso is even beyond that, since he can absorb the powers of his successor as the wrath and vengeance of God.

There are only 2 beings more powerful than him: The Presence and the Great Evil Beast.