WARNING: The following article contains spoilers for Future State: Shazam! #2 by Tim Sheridan, Eduardo Pansica, Julio Ferreira, Marcelo Maiolo, and Rob Leigh, on sale now.
Shazam is and always has been one of the most powerful beings in the DC Universe. As Earth's Mightiest Mortal, he's gone toe-to-toe with Superman on more than one occasion. Shazam has also fought a god in the form of the Spectre, and their fight is revisited in the final issue of Future State: Shazam, albeit with very different results.
In "Future State," the Horsemen of the Apocalypse arrived on Earth. With no other options, the surviving heroes trapped them inside Raven, who was in turn imprisoned within the Rock of Eternity. To keep her contained as well as ensure Shazam could perform his duties, they struck a deal with Neron, separating Billy Batson from Shazam and leaving Billy to guard the door. But this decision had consequences, as any deal made with a devil would. Without Billy as a part of himself, Shazam lacked the wisdom to properly determine good from evil. To compensate for this "lack of vision" Neron gave Shazam his own perceptions, twisting what the hero saw.
This resulted in Shazam murdering several innocent people. It may have been unintentional, but the damage was done and the Spectre was summoned to judge Shazam. Reaching into his mind, the Spectre saw what became of the now separate Shazam and Billy. This had the unfortunate side effect of overwhelming the Spectre with Neron's powers as well as the horror of Shazam's crimes. Unable to handle the strain, he collapsed, and Shazam stabbed him with a piece of the one of the only weapons capable of harming the godlike entity, the Spear of Destiny. This fight is the exact opposite of one that happened between Shazam and Spectre during Infinite Crisis.
The Spectre is one of the most powerful beings in the DC Universe, aptly demonstrated when Eclipso manipulated him into destroying all magic in Day of Vengeance by Bill Willingham, Justiniano, and Pat Brosseau. The god-like entity took down the likes of Briar Blackthorn, an entire family of vampires, and even Doctor Fate. With magic's existence threatened, the Wizard charged Shazam with stalling for time as he found a solution.
Shazam was the champion of the Rock's power, yet the Wizard only believed that Spectre could be stalled. Although these fears proved to be true, Shazam did more than most of the other magical denizens of the DC Universe, holding the Spectre off for a few seconds before the Spirit of Vengeance began siphoning Shazam's magic away. The only thing that turned the tide was when Enchantress temporarily funneled all of Earth's magic into Shazam, empowering him to fight back and nearly destroy the Spectre.
But this would not last long. The strain of the deed pushed Enchantress over the edge and she succumbed to her evil side. With his boost now wearing off, Spectre made quick work of Shazam, knocking him out with a single blow. With their power gap firmly established, it is remarkable that Shazam managed to pull a win this time even if he did have help, and a deadly weapon.