Grey Knights, Space Marines, Arks of Omen, Warhammer 40k, power armor, Nemesis force weapons, psychic abilities, storm bolter, dynamic poses, battle stance, silver and grey color scheme, intricate armor details, purity seals, gothic architecture, spaceship interior, dark ambient lighting, dramatic shadows, close combat, ethereal glow, psychic energy effects, grimdark atmosphere, metallic textures, embossed symbols, action-packed scene, 3/4 view, high contrast lighting, detailed background, space hulk corridors, ominous presence, strategic composition.