The Thousand Sons are a Chaos Space Marine legion in Warhammer 40,000 devoted to the Chaos God Tzeentch, the Changer of Ways. Once loyal Space Marines of the XV Legion, they were cursed with mutation and psychic powers following their fall to Chaos during the Horus Heresy. Each Thousand Sons warrior is a sorcerer gifted with potent psychic abilities, wielding infernal sorcery and harnessing the power of the Warp. They are characterized by their quest for knowledge and arcane secrets, often seeking to manipulate events to fulfill their own enigmatic agendas.