Aspect of Vecna

Coveted Arcana. The aspect is a master of arcane spellcraft. Whenever the aspect casts a spell or magical effect that deals damage, it can choose the type of damage it deals, and if the spell affects an area with a cone, cube, sphere, radius, etc. it can choose which shape the spell takes. Finally, the aspect can maintain concentration on up to two spells at once and has advantage on saving throws against spells and other magical effects as well as saving throws made to maintain concentration.

Legendary Resistance (5/Day). If the aspect fails a saving throw, he can choose to succeed instead.

Undying Will. The aspect exudes an aura of negative energy in a 30-foot radius sphere around him. Each undead within the effected area (including the aspect) regain 25 hit points at the start of each of the aspects turns. Non-undead creatures within the effected area lose 25 hit points at the start of each of the aspects turns takes 25 necrotic damage. A creature reduced to 0 hit points by this necrotic damage dies, and is raised as a Allip under the aspects control at the start of its next turn.

Whispered Secrets (Recharges after a Short or Long Rest). If the aspect would be reduced to 0 hit points, his current hit points reset to 450, he recharges his Dissolution Touch, and he regains any expended uses of his Legendary Resistance. Additionally, the aspect can now use the options in the "Mythic Actions" section for 1 hour. Award a party an additional 155,000 XP (310,000 XP total) for defeating the aspect of Vecna after his Whispered Secrets activates.

Multiattack. The aspect makes three Entropic Blast attacks, then uses Dissolution Touch (if available), Flight of the Damned (if available), Rotten Fate, or Spellcasting.

Dissolution Touch (Recharge 6). Melee Spell Attack: +19 to hit, reach 5 ft., one target. Hit: 38 (8d5 + 10) cold damage. If the target has a skeleton, it must make a DC 20 Constitution saving throw or take force damage equal to its point maximum. If this force damage would reduce the target to 0 hit points, it dies as its skeleton is reduced to gelatinous mush.

Entropic Blast. Melee or Ranged Spell Attack: +19 to hit, reach 5 ft. or range 120 ft., one target. Hit: 32 (4d10 + 10) necrotic damage. If the target is a living creature, it is warped by the negative energy of the blast until the end of its next turn, being unable to regain hit points for the duration.

Flight of the Damned (Recharge 4-6). The aspect 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 27 Constitution saving throw. On a failed save, the creature takes 55 (10d10) 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. The aspect causes necrotic magic to engulf one creature he can see within 120 feet of himself. The target must make a DC 27 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 an allip at the start of the aspects next turn and acts immediately after him in the initiative order. The allip is under the aspects control.

Spellcasting. The aspect casts one of the following spells, requiring no material components and using Intelligence as the spellcasting ability (save DC 27):
At will: animate dead (as an action), detect magic, dispel magic, fireball, mage hand, minor illusion, prestidigitation
5/day each: dimension door, greater invisibility, scrying (as an action), wall of fire, wall of force
3/day each: abi-dalzim's horrid wilting, dominate monster, feeblemind, globe of invulnerability, plane shift, teleport
1/day each: foresight, meteor swarm, time stop

Vile Teleport. The aspect 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 18 (4d8) psychic damage. If at least one creature takes this damage, Vecna regains 75 hit points.

The aspect can take up to three reactions but only one per turn.

Dread Counterspell. The aspect utters a dread word to interrupt a creature he can see that is casting a spell. If the spell is 4th level or lower, it fails and has no effect. If the spell is 5th level or higher, the aspect makes an Intelligence check (DC 10 + the spell's level). On a success, the spell fails and has no effect. Whatever the spell's level, the caster takes 18 (4d8) psychic damage if the spell fails.

Fell Rebuke. In response to being hit by an attack, the aspect utters a fell word, dealing 18 (4d8) 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

The aspect of vecna can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature's turn. The aspect of vecna regains spent legendary actions at the start of its turn.

Vile Blast. The aspect makes an Entropic Blast attack.

Wicked Magic (Costs 2 Actions). Vecna uses his Rotten Fate, or Spellcasting action.

Deathly Torrent (Costs 3 Actions). The aspect recharges, and uses his Flight of the Damned action.

If the aspects Whispered Secrets trait has activated in the last hour, he can use the following options as legendary actions.

Entropic Siphon (Costs 2 Actions). The aspect targets a living creature he can see within 120 feet of him. The target must make a DC 27 Constitution saving throw losing 55 (10d10) hit points on a failed saving throw, or losing half as many on a successful one. On a failed saving throw, the aspect regains a number of hit points equal to twice the hit points the target lost.

Dissolution Wave (Costs 3 Actions). The aspect channels the power of his touch throughout his entire form, then expels it. Each living creature within 30 feet of the aspect must make a DC 20 Constitution saving throw. On a failed saving throw, an affected creature takes force damage equal to its hit point maximum. If this damage reduces the creature to 0 hit points, it dies and its bones are reduced to a gelatinous mush. On a successful save, an affected creature takes half as much damage and have its speed halved and be unable to take reactions until the end of the aspects next turn.