Marvel is highlighting a new Avengers storyline starting in December, by Jason Aaron, Ed McGuinness and Javier Garron, Enter The Phoenix to follow up on their current storyline The Age Of Khonshu dealing with Moon Knight.
Phoenix Force first appeared in Uncanny X-Men #101 in 1976 in the guise of Jean Grey, and was created by Chris Claremont and Dave Cockrum. An immortal and immutable manifestation of the universal force of life and passion, it is the nexus of all psionic energy that does, has, and ever will exist in all realities of the multiverse, the Guardian of Creation, and of the M'Kraan Crystal. The phoenix and those who wield the force, have the power to cut and re-grow any part of the universe, as well as destroy it entirely, which is part of the Phoenix's purpose: "The Judgment of the Phoenix", to burn away the obsolete. The Phoenix Force is described as being "the embodiment of the very passion of Creation—the spark that gave life to the Universe, the flame that will ultimately consume it."
During its time as a sentient and formless mass of energy, it travelled the cosmos and came to be worshipped by several alien races, among them the Shi'ar, who named the entity as Phal'kon, the "sister" of their other gods K'ythri and Sharra.
Jason Aaron has added The Phoenix to his Avengers One Million BC storyline, coming to Earth during the Stone Age, possessing a cavewoman and sharing a romantic relationship with the god Odin. But the best-known version of Phoenix was Jean Grey and her parallel-universe daughter, Rachel, including the classic Phoenix Saga by Claremont and John Byrne. Who this Phoenix will be, we still have yet to be told. Originally planned for the autumn, the =current schedule has shifted the storyline into December 2020.