ce huge darvakka shadow undead 

Perception +29; greater darkvision, lifesense [object Object] feet

Skills Arcana +27, Athletics +29, Intimidation +28, Negative Energy Plane Lore +27, Religion +27, Shadow Plane Lore +27, Stealth +27, Warfare Lore +27

Str +8 Dex +4 Con +6 Int +6 Wis +6 Cha +7

AC  37; Fort +25, Ref +25, Will +31

HP 335, negative healing; Immunities death effects, disease, paralyzed, poison, unconscious; Weaknesses good 10, silver 10; Resistances cold 10

Entropy's Shadow (aura, divine, necromancy, negative) 40 feet. As vanyver, but DC 33 and 4d6 damage.

Sunlight Powerlessness As vanyver.

Speed 40 feet; air walk

Melee [>] horn +31 (magical, reach 10 feet), Damage 3d8+12 bludgeoning plus 1d10 cold and 2d8 persistent bleed

Melee [>] arm spike +31 (agile, magical, reach 10 feet), Damage 3d8+12 piercing plus 1d10 cold

Divine Innate Spells DC 36; 7th harm (×3), paralyze, plane shift (to Material Plane, Negative Energy Plane, or Shadow Plane only); 6th true seeing; 4th darkness (at will), invisibility (×3); Cantrips (8th) detect magic; Constant (8th) air walk

Change Posture [>] The sykever changes between their bipedal and quadrupedal stance. In their bipedal stance, the sykever can use all the abilities in their stat block except Horned Rush. In their quadrupedal stance, the sykever has a Speed of 80 feet but can't make arm spike Strikes, Disarm, cast spells, or use Crush Item.

Crush Item [R] Trigger The sykever gets a critical success to Disarm; Requirements The sykever is in their bipedal stance; Effect The sykever snatches the item and pierces it with their arm spikes. The item becomes broken and falls to the ground in the sykever's space. Items that are already broken aren't further damaged, and an item with 14 or higher Hardness is unaffected.

Draining Gaze [>] (concentrate, divine, necromancy, visual) The sykever fixes their nightmarish gaze on one creature they can see, who must attempt a DC 36 Will save. Regardless of the result, the target is temporarily immune for 10 minutes. Critical Success The target is unaffected.Success The target is enfeebled 2 for 1 round if the sykever is in bipedal stance, or clumsy 2 for 1 round if the sykever is in quadrupedal stance.Failure As success, but the effect lasts 1 minute.Critical Failure As success, but enfeebled 3 or clumsy 3, and the effect lasts 10 minutes.

Horned Rush [>] Requirements The sykever is in their quadrupedal stance; Effect The sykever Strides and then makes a horn Strike.

Book of the Dead, page 83.