Immortality. Z-76 is incapable of death. If his hit points are reduced to 0, he explodes into flames, reforming in another location on the same plane of existence. Use the details from Teleport for creatures within 10 feet of Z-76 when he explodes.

Regeneration. At the start of each of Z-76's turns, he regains 50 hit points.

Demonic Nature. Z-76 requires no food, drink, or sleep.

Luck manipulation. If Z-76 rolls a 1 on any die, he may reroll it and must use the new roll.

Unnatural control. Z-76 cannot break a contract he has signed or tell a direct lie.

Soul Swipe. Z-76 attempts to destroy a creatures soul by force. The target makes a DC 20 saving throw in each ability. If the creature fails on all of the saves, Z-76 destroys their soul, reducing them to 0 hit points and killing them instantly. If they fail on 5 saves, Z-76 nearly destroys their soul, reducing their max and current hit points to 1. If they fail on 4 saves, then their max and current hit points is halved. If they fail on 3 saves, they take 10d10 necrotic damage. If they fail on 1 or 2 saves, they take no damage. If they succeed on all 6 saves, they gain 2d10 temporary hit points. If the targeted creature takes any damage, Z-76 regains that many hit points.

Flame Swipe. Melee Weapon Attack: +10 to hit, reach 20 ft., 3 targets. Hit: 63 (6d10 + 30) fire damage.

Teleport. Z-76 explodes in flame, teleporting to an unoccupied location within 60 feet. An creature within 10 feet of his starting location must make a DC 18 Dexterity saving throw, taking 5d10 fire damage on a fail and half as much on a success.

Multi-Attack. Z-76 uses his Flame Swipe twice and then Teleports.

If a creature uses a melee attack against Z-76 and misses, Z-76 may use his reaction to use his Teleport.

Z-76 has 8 Legendary Actions. He can use any number of them after any creature's turn, and regains expended actions at the start of his next turn.

Flame Swipe (Costs 1 Action). Z-76 uses his Flame Swipe attack.

Move (Costs 1 Action). Z-76 moves up to 100 ft.

Soul Swipe (Costs 2 Actions). Z-76 uses his Soul Swipe attack.

Teleport (Costs 2 Actions). Z-76 teleports.

Energy Saving (Costs 8 Actions). At the beginning of Z-76's next turn, instead of regaining all expended Legendary Actions, he gains 10 Legendary Actions, to a maximum of 20.

Z-76 has 1 Mythic Action. He can only use it during his turn and only if he has less than 200 hit points. If  he starts his turn with 200 hit points or less, roll a d6. On a 5-6 Z-76 regains his Mythic Action

Enough. Z-76 picks any number of creatures in a 100 foot radius. Each creature chosen becomes the target of Z-76's Soul Swipe attack. Each creature is assumed to have failed one extra time*. Z-76 then uses Teleport, then Flame Swipe, then Teleport again, then gains 12 Legendary Actions, which he may use any number of immediately.

*That means that if they fail on 3 of the checks, they are assumed to fail on 4. If they fail none, they are assumed to fail on 1.