Death Knight - Stage 2 (Death Smog)

Boons:

• Death Smog: As an action, you release a thick black smog from your mouth in a 15-foot square. You can choose where to place this square but it has to be in contact with you, spreading around corners. If a creature starts its turn within the smog, they must make a constitution saving throw equal to your transformation save DC. On a failure, they gain 1 SD. The area within the fog is heavily obscured. Undead creatures can see through this fog as if it wasn't there.
  
  You can use this feature once per short rest.

Flaw:

• • Hideous Appearance: Your appearance has grotesquely transformed. Your skin has rotten, only leaving your skeleton. You can suspend this form and manifest the appearance of the creature you once were, but this is taxing and requires concentration. This form is not permanent, and moments of stress are likely to reveal your true nature Your true form may be revealed in the following situations:
    • Becoming Bloodied
    • Concentrating on a spell
    • Gaining the Unconscious condition
    • Entering hallowed ground
    • Choosing to reveal yourself.
    In these events, or times of other extreme emotional or physical stress, a GM can call for a Constitution Saving Throw with a DC based on your current Transformation Stage:
    Stage 1: DC 10
    Stage 2: DC 13
    Stage 3: DC 16
    Stage 4: DC 20