WARNING: The following article contains spoilers for Avengers #24 by Jason Aaron, Stefano Caselli, Luciano Vecchio, Jason Keith and VC's Cory Petit, on sale now.
The current volume of Avengers had the latest incarnation of the team gathering to battle Dark Celestials that had grown dormant on Earth for millennia after battling the prehistoric superheroes defending the Earth. The legacy of the Celestials forming a new lineup of Earth's Mightiest Heroes led to Black Panther becoming the new team's leader and locating the ensemble's headquarters in the long-dead carcass of a Celestial partially entombed in a glacier. The team dubbed the location Avengers Mountain, as they resided and trained in the repurposed Celestial body.
With Cosmic Ghost Rider suddenly appearing on Earth to attack the Avengers at Avengers Mountain, Black Panther unveils a defensive secret drawn straight from the team's new headquarters. As he and Captain America charge into battle to aid Thor, She-Hulk and Captain Marvel against the cosmically and supernaturally powered incarnation of Frank Castle from an alternate future, T'Challa reveals that he has fitted the Black Panther and Captain American uniforms with Celestial energy derived from the new facility itself. This gives both superheroes a significant power boost that helps them turn the tide of battle and bring Cosmic Ghost Rider back to his senses.
However, the two iconic Avengers aren't the only characters to gain access to the vast powers wielded by the Celestials. In Hell, Robbie Reyes continues to race against Johnny Blaze for the netherworld's throne in the mythical Challenge of the Ghost Riders. Knowing the true price of reigning over Hell, the Spirit of Vengeance refuses to yield or take it easy on Robbie, though the younger Ghost Rider puts up an admirable effort in the Hellcharger.
However, as the competition intensifies, Robbie learns that the spirit of Eli Morrow -- from whom he initially gained his hellish powers due to Eli's background as a Satanic serial killer -- is actively hunting him in Hell. And he has an upgrade of his own: The soul of the deceased Celestial from Earth.
Eli informs his nephew that all manner of sentient beings that sinned extensively in life are sent to Hell upon death, even omnipotent beings like the Celestials. As this particular Celestial had wiped out life across multiple planets before its eventual death on Earth, its soul had been imprisoned in Hell for millennia.
Eli used his knowledge of the dark arts to take possession of the Celestial's soul and become exponentially more powerful. With this revelation, Robbie is no longer simply trying to outrace Johnny in their duel but must also elude the hulking, hellish Celestial now fully under Eli's control, as Eli fiendishly looks to kill his nephew once and for all.
The Challenge of the Ghost Riders has separated Robbie Reyes from the rest of Earth's Mightiest Heroes. He is cast off alone in the depths of Hell while his teammates have to contend with a rampaging Spirit of Vengeance of their own in Cosmic Ghost Rider. With the alternate future Frank Castle now brought under control, it seems his recent bout of madness, which led him to attack the team, may have been caused by Eli's corruption of the powerful Celestial in Hell.
Now mentally cleared, Cosmic Ghost Rider could potentially use his powers as a Spirit of Vengeance to transport the rest of the team to Hell. There they could offer Robbie their assistance to stop the demonically powered Celestial and exorcise Eli -- a loose retread of how this roster came together at the very start of the series.
However, the only thing potentially more powerful than a Celestial is one that also wields the forces of Hell. Not even Captain America and Black Panther's upgrades may be enough to save the day.