The Arks of Omen have sown terror and death from one side of the galaxy to the other. Despite the efforts of those who opposed them, their masters have gathered enough arcane artefacts for Vashtorr the Arkifane to fashion his monstrous Key. The hour draws nigh when the daemon and the Despoiler will between them awaken this engine of terrible power. There are still those who can oppose their dark plan. Chief amongst them are Supreme Grand Master Azrael and the many Unforgiven Chapters who fight beneath his banner. Gathering their might, the Dark Angels and their successors answer the Arkifane’s challenge, hoping to quell whatever malevolence he and Abaddon seek to unleash. Nor are they alone in their quest, for Commander Dante races to lead his Blood Angels – and countless other Imperial forces – to the coming battle. For all these grand events, none can compare to the return of a demigod long thought lost to the annals of legend. Lion El’Jonson, Primarch of the Dark Angels, has awoken, and by strange paths has returned to aid the Imperium in its darkest hour. Will the Lion triumph, or will the champions of Chaos unleash a new and nightmarish force upon the galaxy? In this 128-page hardback book, you'll find: – The ongoing narrative of Warhammer 40,000, with galaxy-shaking implications for the Imperium as the Lion and his sons battle to foil Vashtorr's designs – An inspiring showcase of photography and battle scenes, featuring the armies fighting on the planet of Wyrmwood – Additional rules for using four factions in Boarding Actions – Leagues of Votann, Thousand Sons, Adeptus Custodes, and Agents of the Imperium – Rules for playing dramatic Dread Encounters that reshape the very battlefield and recreate climatic moments from the Arks of Omen saga – Rules for explosive Breaching Operation missions that use Killzone: Soulshackle terrain components, as your forces blast through walls and jam hatchways – Datasheets for Lion El’Jonson, Commander Dante, Navis Imperialis units, and Adeptus Arbites squads