WARNING: The following article contains spoilers for Avengers #36, by Jason Aaron, Javier Garrón, Jason Keith and VC's Cory Petit, available now.
At the start of the "Age of Khonshu" storyline, Moon Knight took on some of the most powerful heroes in the Marvel Universe and stole a bit of their power. However, it wasn't for himself but his master, Khonshu. The moon god had a vision of the future, of a universe engulfed in the flames of Mephisto. To prevent this vision from coming true, Khonshu and Moon Knight made a massive power grab. Now, they rule over Earth -- but even with all the power they now possess, it still might not be enough to stop Mephisto.
Therefore, in Avengers #36, Moon Knight goes even further, forsaking his god and turning to a much more powerful cosmic entity: the Phoenix Force.
In Avengers #36, Moon Knight finds himself on the Moon after failing to find Captain Marvel, Iron Man and the Starbrand baby they are both protecting. Moon Knight believes that the Starbrand, one of the most powerful forces in the universe, will help him and Khonshu defeat Mephisto. But while on the Moon, he is approached by the Unseen, a cosmic watcher who tells him there is another cosmic powerhouse, one even more powerful than the Starbrand, that can help him save the Earth: the Phoenix Force.
And the Unseen tells him exactly how to get the cosmic entity's attention.
For the remainder of the issue, Moon Knight locks himself in a battle against Black Panther. The King of Wakanda proves himself the superior fighter, but Moon Knight never once yields. He keeps fighting, enduring a brutal beatdown in order to do what he must. It takes until the end of the issue to realize what he is doing: "praying" to the Phoenix, proving himself as a worthy and devoted host.
Once his "prayer" is finished thanks to a self-inflicted "Fist of Khonshu" punch, the Phoenix travels through the cosmos to find Moon Knight on Earth, choosing him as its new host. As a result, Moon Knight gets a new white and golden costume, and he gets a massive power upgrade as the new Phoenix.
Now, Moon Knight has just become one of the most powerful and dangerous beings in the Marvel Universe. With the abilities of the Phoenix, it's possible he finally has the strength necessary to defeat Mephisto -- and there's no telling what kind of damage he will leave in his wake.
However, we do know what will happen after this. Indeed, the next storyline in Avengers will be "Enter the Phoenix," which will see the Phoenix choose one Marvel character as its next host. Therefore, its stay with Moon Knight will be limited -- but this is the start of something much, much bigger.