Actions

Multiattack. Vecna uses Flight of the Damned (if available), Rotten Fate, casts a spell with a casting time of 1 action or uses an action granted by a Magic Item he's Attuned to. He then makes two attacks with Afterthought.   Afterthought. Melee Weapon Attack: +13 to hit, reach 5 ft., one target. Hit: 7 (1d4 + 5) piercing damage plus 9 (2d8) necrotic damage. If the target is a creature, it is afflicted by entropic magic, taking 9 (2d8) necrotic damage at the start of each of its turns. Immediately after taking this damage on its turn, the target can make a DC 20 Constitution saving throw, ending the effect on itself on a success. Until it succeeds on this save, the afflicted target can't regain hit points.   Flight of the Damned (Recharge 5–6). Vecna conjures a torrent of flying, spectral entities that fill a 120-foot cone and pass through all creatures in that area before dissipating. Each creature in that area must make a DC 22 Constitution saving throw. On a failed save, the creature takes 36 (8d8) necrotic damage and is frightened of Vecna for 1 minute. On a successful save, the creature takes half as much damage and isn't frightened. A frightened creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.   Rotten Fate. Vecna causes necrotic magic to engulf one creature he can see within 120 feet of himself. The target must make a DC 22 Constitution saving throw, taking 96 (8d8 + 60) necrotic damage on a failed save, or half as much damage on a successful one. A Humanoid killed by this magic rises as a zombie at the start of Vecna's next turn and acts immediately after Vecna in the initiative order. The zombie is under Vecna's control.

Bonus Actions

Vile Teleport. Vecna teleports, along with any equipment he is wearing or carrying, up to 30 feet to an unoccupied space he can see. He can cause each creature of his choice within 15 feet of his destination space to take 10 (3d6) psychic damage. If at least one creature takes this damage, Vecna regains 80 hit points.

Reactions

Vecna can take up to three reactions per round but only one per turn.   Fell Rebuke. In response to being hit by an attack, Vecna utters a fell word, dealing 10 (3d6) necrotic damage to the attacker, and Vecna teleports, along with any equipment he is wearing or carrying, up to 30 feet to an unoccupied space he can see.

Lair Actions

Lair Actions On initiative count 20 (losing initiative ties), Vecna takes a lair action to cause one of the following effects; Vecna can’t use the same effect two rounds in a row:

• Shadowplay. Vecna summons one shadow per character. Each shadow appears within 5 feet of a different character. The shadows follow Vecna’s commands (no action required) and last until he uses this lair action again or dies. A shadow acts during initiative count 20 after lair actions have been resolved.
• Drain Life. Vecna casts enervation at 7th level. Vecna doesn't need to concentrate on the spell and the spell ends on initiative count 20 of the next round.
• Mournful Dead. Wailing spirits swarm a 20-foot-radius sphere centered on a point in the lair that Vecna can see. Each creature in that area must succeed on a DC 18 Wisdom saving throw or take 28 (8d6) cold damage and have their movement speed reduced by 15 feet. A creature that succeeds on its saving throw takes half as much damage and doesn’t have their movement speed reduced.