This was Earth

More about the book

A dying red man on a red planet is the key to saving humanity. Johnny Night-Star Angel, a descendant of the first Mars colony witnesses the return of the Sky Gods, both good and bad, as alien ships dot the skies and seed the atmosphere with a semi-sentient virus which turns people into nightmarish monsters. Accompanied by his two cats, Gallant and Goofus, aided by the other dimensional beings which his Hopi ancestors called Kachina, and plagued by memories of those who have fallen, Johnny must face down the dark champion of the invaders and find an ancient secret on Mars to save both Earth and Mars from extinction.