Black knife assassin (Elden Ring)

Sneak attack. If the assassin has advantage on an attack it does 2d6 extra damage. And the creature falls prone.

The creature has advantage on stealth rolls

The creature has advantage on attack rolls against any creature it has surprised.

Spellcasting. The Black Knife assassin is a 3rd-level spellcaster. Its spellcasting ability is Wisdom (spell save DC 15, +7 to hit with spell attacks). The Black Knife assassin  has following Elden Ring  spells prepared:
1st level (3 slots): Blade of death
2nd level (2 slots): 

Action Name. Enter the description for your action.

Action Melee Attack. Black knife Attack: +7 to hit, reach 5 ft., 1 target. Hit: 6 (1d4 + 4) piercing and 6 (1d4 + 4) necrotic damage. 

The assassin can dash, hide, and disengage as a bonus action

The assassin may also go invisible as a bonus action.

Uncanny dodge. Reaction to half damage

The creature adds its proficiency bonus to its AC against one melee attack that would hit it as a reaction.