The Four Horsemen of the Apocalypse
were actually agents of the alien race known as the Axi-Tuns
.They have been active for billions of earth years serving the empire .They conquered primitive Earth for about a century until another alien race that was more powerful than they were defeated them and banished them from our solar system.When they returned to the Axi-Tun Empire they were branded cowards and banished to wander the universe for all eternity .After roaming the universe for many centuries ,they tried to reconquer the Earth but were opposed and defeated by the Fantastic Four
.Somehow they were captured by The Stranger
and were his prisoners
in his laboratory ,until the Overmind
released them .They attacked Quasar
who defeated them .