Ultimate Marvel Cinematic Universe Wikia

The Phoenix Force is one of the oldest known cosmic entities, representing all current and future life, as well as the forces of creation and destruction. The Phoenix is immortal, indestructible, and mutable manifestation of the prime universal force of life. Born of the void between states of being, the Phoenix Force is a child of the universe. It is the nexus of all psionic energy which does, has, and ever will exist in all realties. It is said that the Phoenix Force is the spark that gave life to the universe. The Phoenix has the power to cut and regrow and parts of the universe, as well as destroy it entirely as part of its purpose, making it among the most feared beings in the entire universe. During its time as a sentient entity, it traveled the cosmos just like other cosmic beings. Though it began as a formless mass of energy, it adopted the form of a firebird. It has, at times, chosen various hosts to live within, granting the vessel outstanding power to create and destroy.