Shadow Mage

Empowering Shadows. While in dim light or darkness, the mage deals an extra 4d6 necrotic damage on melee spell and weapon attacks.

Dark Regeneration. If the Shadow Mage starts their turn in dim light or darkness, they regain 20 hit points. If the Shadow Mage takes radiant damage, this trait doesn't function at the start of their next turn, The Shadow Mage dies only if it starts its turn with 0 hit points and doesn't regenerate.

Shadow Weave. The Shadow Mage uses Shadow Weave to cast their spells. Any spell of the Illusion, Enchantment, or Necromancy school cast by the Shadow Mage is enhanced, melee and ranged spells have an advantage, while spells with saving throws give the target disadvantage on the roll. While if cast at the Shadow Mage, they have an advantage on saving throws and taking half damage.

While the spells of Evocation or Transmutation school are more effective against the Shadow Mage. Any melee and range spells have the advantage to hit, and the Shadow Mage has a disadvantage on saving throws. 

Spellcasting. The Shadow Mage is an 14th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 18, +10 to hit with spell attacks). The Shadow Mage has the following wizard spells prepared:

Cantrips (at will): Chill Touch, Friends, Mind Sliver, Toll the Dead, Minor Illusion, Acid Splash

1st level (4 slots): Cause Fear, Shield, False Life, Hideous Laughter, 

2nd level (3 slots): Blindness/deafness, Hold Person, Ray of Enfeeblement, Tasha's Mind Whip, Phantasmal Force

3rd level (3 slots): Vampiric touch, Counterspell, Dispel Magic, Fear, Life Transference

4th level (3 slots): Greater Invisibility, Blight, Raulothim's Psychic Lance, Phantasmal Killer

5th level (3 slots): Dominate Person, Creation, Negative Energy Flood

6th level (2 slots): Mental Prison, Soul Cage

7th level (1 slot): Finger of Death

Multiattack. The Shadow Mage makes two attacks with its shadow blades or casts a spell and makes one attack with the shadow blade.

Shadow Blade. Melee Weapon Attack: +13 to hit, reach 5ft., one target. Hit; 22 (3d8) psychic damage.

Lashing Shadows (Recharge 5–6). Each creature within 60 feet of the Mage, except other Mages, must succeed on a DC 18 Dexterity saving throw or take 27 (6d8) necrotic damage.

Shadow Parry. The Shadow Mage adds 3 to their AC against one melee attack that would hit them. To do so, the Mage must see the attacker and be in dim light or darkness, and they use the shadows around them to parry the attack.