Air-Walker is a villain from the Marvel comics, He is one of Galactus' Heralds and manifests its Cosmic Power via control of Air.
Gabriel Lan was from the planet Xandar, birthplace of the Nova Corps, as well as an astronaut and explorer. When he met the world-devouring Galactus, he joined him not out of power-lust or a deal, but to explore the wonders of creation with him. This voluntary joining made Lan the favorite herald of Galactus, and when Lan died accidentally, Galactus built an android in his memory. Reaching Earth during one of Galactus' periodic efforts to go around his oath and devour it, the android posed as the Archangel Gabriel and attempted to make Earth surrender using the fears of divine judgment many Humans hold. The Air-Walker android was eventually destroyed by the Fantastic Four, who were aided by the Silver Surfer, who did not at the time realize the construct was made in memory of his direct successor as Galactus' herald. A large-scale battle with Galactus himself quickly followed.
Later, the android revived and battled Thor, who defeated it with the aid of Galactus' next herald, Firelord, who was also from Xandar and had been a friend of the real Gabirel Lan. Still later, Lan, the Surfer and another former herald, Terrax, revived the android once again in order to take on Morg, a ruthless herald that was more treacherous than Galactus realized. Lan possesed the power cosmic as Air-Walker, while the android possesed some access to it as well, making both extremely powerful on their own terms.
The Avengers Earth's Mightiest HeroesHe oversaw the construction of a device in the mountains that would help Galactus consume the Earth. In his battle against the Avengers, Air-Walker takes on a group of superheroes consisting of Thor, Vision, Black Widow, Luke Cage, and Falcon, Thor and Vision battle the herald while the others prepare explosives to destroy the machine. Air-Walker is eventually severely weakened by Thor's lightning before being destroyed by Vision's laser.