Amorphous: The shadow can move through a space as narrow as 1 inch wide without squeezing.

Superior Shadow Stealth: While in dim light or Darkness, the shadow can take the Hide action as a Bonus Action. Its stealth bonus is also improved to +8.

Spellcasting. The Lut'B is a 5-level undead/shadow spellcaster. Its spellcasting ability is 13 (spell save DC 12, +1 to hit with spell attacks). The Lut'B has following Necromatic spells prepared:
Cantrips (at will): Chill Touch
1st level (2 slots): Cause Fear, Inflict Wounds 
2nd level (1 slot): Blindness/Deafness
3rd level (1 slot): Animate Dead
4th level (1 slot): Blight
5th level (1 slot): Negative Energy Flood

Shadow Claw: +2 to hit, reach 5 ft., one target. Hit: 5 (1d10 + 2) slashing damage. 

Phantom Needle: Attack: +2 to hit, range 25/75 ft., one target. Hit: 5 (1d8 + 1) poison/piercing damage.