False Appearance. While the Angel remains motionless, it is indistinguishable from an inanimate statue.

Petrifying Defence. While a character observes the angel without blinking, it gains the petrified condition and cannot move or attack. While in this state its resistances become immunities and gains all the effects of a petrified creature. A character can use his or her reaction to cast out a 75ft cone and any angel caught in the cone will be petrified on its next turn. After 5 uses of this ability, a character must make a Constitution saving throw with a DC of 5 to succeed on each subsequent turn. This DC increases by 5 each time it is attempted up to a maximum of 15. The area of this ability is halved if the creature is in low light (without darkvision) and cannot be used by a blinded character, creatures relying on blindsight to see, those in complete darkness, undead or constructs. While not petrified and working with other Angels, the Angel can use its reaction to ensure that it doesn't look at another Angel and If two angels fail to use their reaction and look at each other then they remain petrified until something breaks the line of sight such as a Darkness spell. 

Pack Tactics. The Angel has advantage on attack rolls against a creature if at least one of its allies is within 5 feet of the creature and the ally isn't incapacitated.

Multiattack. The Angel makes two attacks: one with its bite and one with its claws or can use its draining touch.

Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 7 (1d10 + 2) piercing damage.

Claws. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 6 (1d8 + 2) slashing damage.

Draining Touch. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 9 (1d12 + 3) necrotic damage and the Angel heals equal to the damage done. The targets maximum hit points are lowered based on the necrotic damage done and the character ages a number of years equal to the damage of the attack. The lost hit points are restored after a long rest but the additional years of age can only be restored by a greater restoration spell or similar magic. Each time a character suffers a draining touch that takes them above a venerable age (e.g. 70 with humans) they gain a level of exhaustion and after gaining 6 levels the victim turns to ash.

Ethereal Action. The Angel can use its bonus action to dash, disengage or hide and is ethereal while it moves allowing it to pass through objects and ignore difficult terrain. The Angel does not provoke attacks of opportunity while using its ethereal action. 

Cursed Rebuke. While the angel is petrified by its petrifying defence ability it can as a reaction use its cursed rebuke ability to cast spells depending on the damage it takes. if the Angel takes 1 hit point of damage or more in this from an attack it can use its reaction to inflict a curse on the target as if it had cast a 'Bestow Curse' spell on the attacker. If the angel takes 5 hit points of damage or more it can cast 'Blindness' on the attacker and if the Angel takes 10 hits points of damage then a cloud of darkness seeps out of the wound replicating the effects of a 'Darkness' spell centred on the alien. The Angels spell save DC is 13.