Medium Aberration, Any Evil Alignment

Armor Class: 14

Hit Points: 136 (16d8+64)

Speed: 30 ft., fly 45 ft. (hover)

STR 6/-2

DEX 16/+3

CON 18/+4

INT 10/+0

WIS 13/+1

CHA 14/+2

Evil Manifested. Echo of Black Stars is the manifestation of any villainous tale or memory permeated in the minds and hearts of mortals.
As an action, it can take the appearance and personality of any important evil-aligned creature that is a part of some collective knowledge, such as tales, myths, history, etc…
This illusory appearance becomes spectral and transparent, with the starry true form of the being appearing inside its body, when the Echo has half or less of its maximum hit points.
If the Echo takes the form of a creature with size other than medium, its own creature size changes to that of the creature.

• When Echo takes the appearance of a creature, it can also choose up to two ability scores and it replaces its own ability scores with that of the chosen creature. If the ability scores of the chosen creature have a modifier of +6 or more, they become +5 instead. 
• When the Echo has an appearance of a creature, its own attack and abilities can change their appearance as well to fit the new form. 

Light of Darkness. Echo of Black Stars can create a 90-foot cone from itself that turns any bright light into magical darkness, and causes any source of bright light to give off magical darkness instead. At the start of each of its turns, the Echo decides which way the cone faces and whether it is active. This cone is invisible, but gives a faint purple aura if a creature can detect magic or see through invisibility. 

Any creature that ends their turn in the magical darkness created by this effect must make a DC 14 Wisdom saving throw, taking 2d10 psychic damage, becoming frightened until the end of their next turn, and giving the Echo one charge of Malevolence on a failure.

Malevolence. Echo of Black Stars is fueled by the evil it causes and that happens around it. Through some of its abilities, or when an evil act happens in its line of sight, Echo gains 1 charge of Malevolence. The evil acts can be for example attacking innocents, killing a downed creature, summoning undead, etc…Whether an act gives charges of Malevolence is determined by the GM. 

Echo can have up to 10 charges of Malevolence at a single time, and it can expend them in the following ways. 

• Imitation of Power (1-5 Charges).  If the Echo has the appearance of a creature that had the Spellcasting ability, it can expend up to 5 Malevolence Charges to cast a spell from the creature’s spell list of the same level as the amount of charges spent. (Spellcasting DC 14, +6 to hit with spell attacks)

• Darkest Night (2 Charges). As a bonus action, Echo can create an aura of Magical Darkness within 15 feet of itself that lasts until the start of its next turn, the area has the same effects as the Magical Darkness created by Light of Darkness

• Legendary Evildoer (2 Charges). When a creature within 60 feet of the Echo ends their turn, it can spend 2 Malevolence charges to make one Villainous Strike and move up to half of its speed. It can only use this ability twice until the start of its next turn. 

• Malevolence Breeds Malevolence (4 Charges). Echo uses its bonus action to immediately recharge its Splintering Shard of Malevolence Attack

• Rise my Minions (5 Charges). Echo uses its bonus action to summon an evil monster of CR 1 or lower within 30 feet of it that lasts for 1 hour. Echo can have up to four of these minions at a single time. These Minions share the Echo’s Initiative and play directly after it.

Actions.

• Multiattack. Echo of the Black Stars makes two Villainous Strikes

• Splintering Shard of Malevolence (Recharge 5-6). Ranged Spell Attack: +7 to hit, range 120 ft., one target. Hit:13(3d6+3) piercing damage. The target must choose to either to take additional 33 (6d10) psychic damage, or once they go to 0 Hit Points within the next minute, Echo gains 2 charges of Malevolence and the target will gain 1 failed death saving throw and any creature within 30 feet of them that is hostile to the Echo becomes immediately targeted by the Splintering Shard of Malevolence attack.

• Villainous Strike. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit:  17(4d6+3) necrotic damage. The creature can choose to take additional 11(2d10) psychic damage, or Echo gains one charge of Malevolence.
  Critical Hits with this attack make the target frightened until the end of their next turn, and make the Echo gain an additional charge of Malevolence. 

• Spreading Fear. Echo chooses an area with a 5-foot radius within 60 feet of it. Any creature in the area must make a DC 14 Wisdom saving throw, being forced to move up to their movement speed in a direction of the Echo’s choosing on a failure;once the affected creature finishes its movement, it takes 22(4d10) psychic damage. On a success, the creatures only take half damage and are not forced to move.
  Echo gains one charge of Malevolence for each creature that fails their saving throw against the effect.