Ki Points. The assassin has 20 ki points available. The DC to resist their effects is 19.
Martial Arts. The assassin uses Dexterity for both damage and attack rolls while using monk weapons or an unarmed strike. When using the attack action on their turn, they can make one unarmed strike as a bonus action.
Evasion. If the assassin makes a successful Dexterity saving throw against an effect, they take no damage from the effect. On failed save, they take half damage.
Diamond Soul. The assassin may spend 1 ki point to reroll a failed saving throw, but must use the second result.
Empty Body. As an action, the assassin can spend 4 ki points to become invisible for 1 minute. During that time, they also have resistance to all damage except force damage.
Touch of Death. When the assassin reduces a creature within 5 feet to 0 hit points, they gain 25 temporary hit points.
Mastery of Death. When the assassin would be reduced to 0 hit points, they can expend 1 ki point (no action required) to drop to 1 hp instead.
Multiattack. If using the Attack action, the assassin may attack twice, rather than once per turn.
Unarmed Strike. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: (1d10 + 5) bludgeoning damage
Sling +1. Ranged Weapon Attack: +11 to hit, reach 30 ft., one target. Hit: (1d4 + 6) bludgeoning damage.
Tail. Melee Weapon Attack: +11 to hit, reach 15 ft., one target. Hit: 15 (2d8 + 6) bludgeoning damage.
Hour of Reaping. Once per encounter, the assassin can unleash an aura tied to the fear of death. Each creature within 30 feet that can see the assassin must succeed on a DC 19 Wisdom saving throw or be Frightened of the assassin until the end of their next turn.
Touch of the Long Death. The assassin can touch one creature within 5 feet of them, and expend 1 to 10 ki points. The target must make a Constitution saving throw, taking 2d10 necrotic damage per ki point spent on a failed save, or half as much damage on a successful one.
Acid Breath (Recharge 5–6). The dragon exhales acid in a 15-foot line that is 5 feet wide. Each creature in that line must make a DC 19 Dexterity saving throw, taking 22 (5d8) acid damage on a failed save, or half as much damage on a successful one.
The dragon 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 dragon regains spent legendary actions at the start of its turn.
Detect. The dragon makes a Wisdom (Perception) check.
Tail Attack. The dragon makes a tail attack.
Wing Attack (Costs 2 Actions). The dragon beats its wings. Each creature within 10 feet of the dragon must succeed on a DC 19 Dexterity saving throw or take 13 (2d6 + 6) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.
Lair and Lair Actions
Black dragons dwell in swamps on the frayed edges of civilization. A black dragon’s lair is a dismal cave, grotto, or ruin that is at least partially flooded, providing pools where the dragon rests, and where its victims can ferment. The lair is littered with the acid-pitted bones of previous victims and the fly-ridden carcasses of fresh kills, watched over by crumbling statues. Centipedes, scorpions, and snakes infest the lair, which is filled with the stench of death and decay.
Lair Actions
On initiative count 20 (losing initiative ties), the dragon takes a lair action to cause one of the following effects; the dragon can’t use the same effect two rounds in a row:
- Pools of water that the dragon can see within 120 feet of it surge outward in a grasping tide. Any creature on the ground within 20 feet of such a pool must succeed on a DC 15 Strength saving throw or be pulled up to 20 feet into the water and knocked prone.
- A cloud of swarming insects fills a 20-foot-radius sphere centered on a point the dragon chooses within 120 feet of it. The cloud spreads around corners and remains until the dragon dismisses it as an action, uses this lair action again, or dies. The cloud is lightly obscured. Any creature in the cloud when it appears must make on a DC 15 Constitution saving throw, taking 10 (3d6) piercing damage on a failed save, or half as much damage on a successful one. A creature that ends its turn in the cloud takes 10 (3d6) piercing damage.
- Magical darkness spreads from a point the dragon chooses within 60 feet of it, filling a 15-foot-radius sphere until the dragon dismisses it as an action, uses this lair action again, or dies. The darkness spreads around corners. A creature with darkvision can’t see through this darkness, and nonmagical light can’t illuminate it. If any of the effect’s area overlaps with an area of light created by a spell of 2nd level or lower, the spell that created the light is dispelled.
Regional Effects
The region containing a legendary black dragon’s lair is warped by the dragon’s magic, which creates one or more of the following effects:
- The land within 6 miles of the lair takes twice as long as normal to traverse, since the plants grow thick and twisted, and the swamps are thick with reeking mud.
- Water sources within 1 mile of the lair are supernaturally fouled. Enemies of the dragon that drink such water regurgitate it within minutes.
- Fog lightly obscures the land within 6 miles of the lair.
If the dragon dies, vegetation remains as it has grown, but other effects fade over 1d10 days.