Warhammer 40,000: Codex: Grey Knights (9th Edition (DE))

The secretive and sinister 666th Chapter of Space Marines are a force of elite warriors, even beyond their Adeptus Astartes kin. Each member of the Chapter has an affinity for the powers of the warp, and they can channel their gifts in battle to blast their foes apart with bolts of energy as well as the might of their arms. Clad in power armour of unusual design, and armed with weapons of rare potency, this small but deadly army strikes from their hidden base on Titan, more than a match for the strongest enemies the Imperium must face