Chronoreaper

Out of Phase. The Chronoreaper has no order in the initiative. Instead, it can choose to take its turn for this round at the end of any other creature’s turn.

Inevitable March. The Chronoreaper is immune to any effect that would reduce its available speed on a turn, including difficult terrain, as well as being immune to the effects of Time Stop and Slow. In addition, by spending 1 minute concentrating, it can overcome almost any barrier intended to keep it at bay in a way that takes the least effort. The only barriers it cannot overcome are those created by the effects of a Wish spell, or those created by deities of time.

Multiattack. The Chronoreaper makes three Phasing Slash attacks. It can replace one of these attacks with any of its other actions.

Phasing Slash. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: (2d10+7) slashing damage. The Chronoreaper can move up 10 feet without provoking opportunity attacks.

Temporal Rip. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: (1d8+7) slashing damage. The target makes a Wisdom saving throw, DC 17. On a failure, the target is temporarily ripped from its own timeline and relives a past moment. The Chronokeeper can choose any single instance of damage or effect the target took within the last minute, and apply it again. This damage cannot be used for this effect again in the future.

Phantom Blink (Recharge 6). The Chronoreaper blinks briefly out of time to a period in the future, and then instantly returns to a point it can see up to half of its speed away. After 1d4 creature’s turns have passed, that version of the Chronoreaper appears at the point where the original Chronoreaper used this ability. It makes one full turn, during which, it cannot use Phantom Blink or No More.  Any damage it takes is instead transferred to the original Chronoreaper. After that turn, it disappears. If it does not end its turn in the space the Chronoreaper originally chose to reappear in, the original Chronoreaper takes 4d10 Force damage.

No More (1/day). The Chronoreaper casts the Time Stop spell.

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

Detect. The Chronoreaper makes a Wisdom (Perception) check.

Phasing Slash. The Chronoreaper makes one Phasing Slash attack.

Temporal Rewind (Costs 3 Actions). The Chronoreaper chooses one weapon attack, class feature, or spell that the previous creature used on its turn. Time is rewritten so that the action never occurred.