Abyssal Armor. Non magical weapons do only 1/2 damage, 5 points of magical damage reduction per instance.  As part of her Abyssal Armor, and using an unused bonus action, the Vjeshitza may "return" and one missile (magical or normal including spells) to its sender.  This is called "Return to Sender" and is part of the Abyssal Armor trait.  The Vjeshitza must have use of at least one hand and arm to do this.  Or if she chooses she can "Redirect" providing she is in Fiend form she can send the missile to another target within sight and range.  She may redirect in humanoid form, but this requires 1 action.

The Vjeshitza is also 50% immune to all detection, scrying and mind reading attempts on her.  After any DC check there is a 50% failure to any of these attempts against her.

Telepathic Bond. The fiend ignores the range restriction on its telepathy when communicating with a creature it has charmed. The two don't even need to be on the same plane of existence.

Shapechanger. The fiend can use its action to polymorph into a Small or Medium humanoid, or back into its true form. Without wings, the fiend loses its flying speed. Other than its size and speed, its statistics are the same in each form. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.

They can also shape shift into domestic pets or even livestock or wild animals.   They can change form at will as a bonus action while in Fiend form  or 1 action if in humanoid form.  They are unable to fly in this form, unless the creature they change into can also fly.  They may cast spells in animal form.  The effect is otherwise the same as polymorph self.

Darkvision 90', See Invisibility 60'

Actions:

Cruel Laughter: As a bonus action in any form, the Vjeshitza can cause an audible cruel feminine laughter that only the target hears.  Those affected ( Constitution DC 13) may not cast spells that require concentration, cast mind affecting spells, use any form or non-spoken mental communication, psionics, or cast illusions.  Additionally those affected suffer a -3 to their initiative.

Number affected: potentially all within 60', duration 6 turns

Vjeshitza may use Cruel laughter 2 /day.

Abyssal Haste: Vjesshitza can opt to use 2 actions in 1 round up to 2 times per day. They may still use their bonus actions and at will abilities when using Abyssal Haste. Optionally They may decide to use 3 actions in one round 1/day.  She may invoke Abyssal Haste at any point during her turn, but not while in animal form.

Flight: Vjeshitza can fly at will in fiend form - OR - by "deploying" her wings as a bonus action while in humanoid form.

Teleport, Dimension Door, Blink: Vjeshitza can  teleport without error 2 day and dimension door 1 per day and blink 2 times per day as a bonus action while in Fiend form or as 1 action in humanoid form. 

Abyssal Charm. The effect is very much like charm except that the Vjeshitza may attempt to charm all targets within 10' of her.  ( Wisdom Dc 15).  This she may do as a bonus action while in Humanoid form or 1 action while in fiend form.  She may NOT exclude anyone in the areas of effect from the Charm attempt without concentration.

She may attempt to charm a singular individual within 10' while in humanoid form but this requires a full action.  She may not attempt to charm a singular individual while in Fiend form unless she also uses her bonus action.

Abyssal Seduction: Adding her bonus action to the attempt to charm a singular individual while in humanoid form makes the Wisdom DC check 16.  The Vjeshizta will always attempt the Abyssal Seduction in the form of a being that the would be target would likely find attractive.

Charm Kiss. The Vjeshiza can kiss a creature an charm it automatically if the creature kisses the Vjeshitza (in any form)  willingly. Unwilling targets get a DC 15 Constitution check.

Etherealness. The Vjeshitza magically enters the Ethereal Plane from the Material Plane, or vice versa.

Gate: Vjeshitza may gate in up to 1d4 vampires (counts as casting a spell). The vampires will likely be individuals whom she has already converted by her Abyssal Bite (Legendary Action). But occasionally more powerful Vjeshitza may elect to gate in other forms of vampires.

Spells:  Vjeshitza are able to cast spells from any school of magic not prohibited by alignment.  They may only cast as many spell levels per day equal to their challenge rating (typically 10) by can range from 7 to 12,even higher on very rare occasions.

Melee: Vjeshitza are dual wielders and use flaming whips and scimitars primarily as weapons and these are always magical to varying degrees.  They may opt to use the whip as a kind of lasso to bind an opponent - or - to retrieve / grab and item.   When lassoing an opponent, the lassoed victim must make either a strength or dexterity save (DC 14) or suffer a bite attack.

General: These weapons range from +3 to +6 to hit depending on the individual.  The damage is by weapon type plus the to hit bonus at a minimum and can scale up by dice type in terms of damage (1d8 becoming 1d10) as the power of the Vjeshitza increases by appointment or experience or both.  The weaker versions of these weapons crit on a natural 19 and get as fearsome as critting on a natural 17.

Whips: Whips will range in power based on the strength of the Vjeshitza.  But the following will apply at a minimum. 

When used as a combat weapon the whips are created to cause severe pain.  Each successful hit of the whip does the normal physical damage, plus flame damage starting at 1d4.

The pain aspect must be saved against.  Each failure of a constitution save upon being hit by the whip means the victim is under the same effects as if cursed (opposite of bless spell).  The Curse effect lasts 1d2 turns.

Scimitars: Like the whip, the scimitar of a Vjeshitza will have certain minimal qualities. 

The scimitars are either swords of sharpness and cause an additional bleed damage die roll or more fearsome could be vorpal.  

Any non-Abyssal creature that attempts to use a Vjeshitza's weapon must make a DC 14 constitution check or take 1d10 hp of damage and 1d2 constitution points of spirit damage per attempt to use the weapon.  For good aligned creatures / characters, the DC is 16.

Claws (2) / Bite (Fiend Form Only). Melee Weapon Attacks: +5 to hit, reach 5 ft., one target. Hit:  (1d4 + 3) slashing damage plus make a DC 14 Constitution save or take 1d2 constitution points of damage.  The Bite is Abyssal Bite (see Legendary Actions)

See Abyssal Armor in Special Traits section

Abyssal Admonition: Vjeshitza have an ability that is the demonic version of hellish rebuke.  Upon being struck, and as a bonus action while in fiend form or humanoid form (not animal form), Vjeshitza may select any two targets that can see them within 90' and cause reflexive damage to be done to them.

The effect lasts for 1d4 rounds.  So any and all damage done to her, will be done to them.  The would be victim makes a DC 12 Constitution check.  If the DC check is successful, the would be victim takes only half. A Natural 20 on the DC check breaks the Abyssal Admonition on that person and they take no damage that round.

Once affected by the spell, range is not a factor for the afflicted.  They can run and hide, but they cannot escape Abyssal Admonition.

Abyssal Bite: As vampires the Vjeshitza drain constitution and can opt to drain 1 to 4 d6 points of constitution per bite (her option).  She may only want to weaken the victim for her own purposes. 

A character who is reduced to zero constitution dies.  No confirmation rolls are required.  The dead individual will rise in 24 hours as a normal vampire with the same stats the individual had in life plus the standard NPC vampire abilities.  This now NPC vampire is entirely in service to the Vjeshitza. This character is normally converted from PC to NPC at this time.

The bites also cause 1HP of damage per point of constitution lost.  Both the hit points and constitution can be healed with the points of constitution counting as three hit points each.

Vampires created by Vjeshitza points have the total HP and Constitution that the character had in life.