Black Fox

Keen Senses: Foxes have advantage on Wisdom (Perception) checks that rely on sight or smell.

Shadow Stealth: while in dim light or darkness, the fox can take the hide action as bonus action

Fox Pack: If the Foxes are in a pack of 3+ every creature in sight must do a Charisma saving Throw or they will get Intimidated.

Radiant Touch: After every attack that hits, the hitted Creature must do a DC10 Con saving throw or they will get radiated(very low). If they get hit again and they are still radiated the radiation intensitiy stacks up by one up to Deadly.

Bite. Melee Weapon Attack: +7 to hit, reach 7 ft., 1 target. Hit: 2d8 + 4 piercing damage

Claw attack(Slashing). Melee Weapon Attack: +8 to hit, reach 5 ft., 1 target. Hit  3d6 + 1 slashing damage

Stealth. The creature attempts to retreat in the shadows and hide. The creature is not to be seen without being in a 5 ft. radius within it. While in this state the creature cannot attack. If it attacks then it will show again.

Clairvoyance. Casting Time: 1 act. , Range: 1mile, Duration: 2 Minutes, Choose between seeing or Hearing

Howling. Range: 60 ft. , buff duration: 1 minute ,Cooldown: 5h. The creature attempts to Howl and gets for 10 Minutes 2d10 + 3 temporary Hitpoints.

Hellfire. The creature calls for the vengeful flame of death with its black flames and attempts to burn it's enemies. The Targets must do a DC16 Dex saving throw, if it succeeds the Targets in range will get  2d10 + 2 Fire damage , on a failed throw the targets don't take damage. The flames are not extinguishable, Reach: 30 ft., up to 5 targets

Hide: make a Dexterity (Stealth) check in an attempt to hide.

Abyssal Help: If 5 minutes passed after fighting and 3+ Foxes are still alive, they will call an abyssal deathworm. Abyssal deathworms are the same as normal deathworms but they have radiant, acid and poison immunity.

Soulstealing. If the creature is below 5 hp it attempts to steal the soul of a single hostile creature within a 15 ft. radius of and consume it it. The creature must do a DC 20 charisma check. If it succeeds it steals the Soul of one target and consumes. The target will die instantly and it's soul will not wander of to another plane of existance. If it fails the creatures soul will crumble apart and the creature is now only an empty vessel without life.