Valthrix-Reckoning, Recursive Enforcer

Echo Matrix Core (Recharge 5–6)
As a bonus action, Valthrix teleports back to the space it occupied at the end of its last turn (if unoccupied). This teleportation leaves behind an unstable duplicate that explodes at the end of Valthrix’s current turn: each creature within 10 ft must succeed on a DC 16 Dexterity saving throw or take 14 (4d6) force damage.

Recursive Strike (Once per turn)
When Valthrix deals damage with a melee weapon attack, it may delay the damage until the start of its next turn. If the target attacks or casts a spell before then, the damage is maximized.

Chrono-Absorption Field
The first time Valthrix takes force, psychic, or thunder damage on a turn, it gains temporary hit points equal to half the damage taken.

Legendary Constructsense
Valthrix always acts on the first initiative count (even on tied rolls) and cannot be surprised.

Multiattack.
Valthrix makes two Echo Cleaver attacks and one Pulse Swipe if available.

Echo Cleaver (Melee Weapon Attack)

+8 to hit, reach 5 ft., one target.
Hit: 15 (2d8 + 4) force damage. On a hit, the target’s shadow blurs and its next attack has disadvantage if made before the end of its next turn.

Pulse Swipe (Recharge 4–6)
A slashing force wave arcs outward. Each creature within a 15-ft cone must make a DC 16 Dexterity saving throw, taking 22 (5d8) force damage on a failure or half on a success. Any creature that fails is pushed 10 ft and knocked prone.

Temporal Concussion (1/Day)
Valthrix emits a temporal shockwave. All creatures within 30 ft must make a DC 16 Constitution saving throw. On a fail:

• The creature loses its reaction until the end of its next turn.
• Its speed is halved for 1 minute.
• It takes 16 (4d6 + 2) psychic damage.

Echo Matrix Core (Recharge 5–6)
As a bonus action, Valthrix teleports back to the space it occupied at the end of its last turn (if unoccupied). This teleportation leaves behind an unstable duplicate that explodes at the end of Valthrix’s current turn: each creature within 10 ft must succeed on a DC 16 Dexterity saving throw or take 14 (4d6) force damage.

Legendary Actions (3/round)

Mirror Step.
Valthrix teleports up to 30 ft to a space it can see.

Echo Recall.
Valthrix recharges its Echo Matrix Core.

Phantom Strike (Costs 2 Actions).
Make one Echo Cleaver attack against any creature within 10 ft of an Echo Marker (left behind by Echo Matrix Core).

Death Effect: Echo Collapse

When Valthrix drops to 0 HP, its echo engine detonates. All creatures within 20 ft must succeed on a DC 16 Dexterity save or take 18 (4d8) force damage and be blinded until the end of their next turn. On success, take half damage and no blindness.