– Background for Traitor Titan Legions and Knight Houses – Revised rules for assembling your battlegroups – Rules for 16 Traitor Titan Legions, including Legio traits, Stratagems, and wargear – Rules for 12 Traitor Knight houses – 19 different maniples to use with your Titans – Allegiance rules for Traitor Titan Legion Battlegroups, Questor Traitoris, and Questor Mechanicus – Background and rules for fielding Corrupted Titans, mutated god-engines fielded in the latter days of the Horus Heresy – 51 Stratagems for use by Traitor battlegroups – 11 Titan upgrades – A comprehensive list of weapons available to each Titan, including weapon traits not featured in the core rulebook