Chaos Battletome: Everchosen is a full colour, 120-page hardback book that contains the background story of Archaon, the Varanguard and the Gaunt Summoners, three Battleplans (instructions that allow you to fight battles based around their narrative, with special rules and layouts), colour schemes and photographies of the various Chaos warbands, six Warscroll Battalions (formations that give access to additional, powerful abilities), and an A5 transfer sheet with the marks of Archaon.