Mark of the Infernal

As a bonus action, you consciously release the volatile power sealed within you.  Infernal fire surges through your veins, granting you hellish vitality, speed and perception for 60 seconds:

• Add temporary hitpoints equal to your max HP.
• You gain resistance to damage from fire and nonmagical attacks.
• You are immune to fear and paralysis.
• Your movement speed is doubled.
• You gain an extra action during combat.  Casters may use an additional spell, rogues may use an additional sneak attack.
• You gain advantage on all attacks and saving throws.
• Your passive perception increases by 2 points.
• If you reduce a creature to zero hitpoints, restore 1d4 hitpoints.

Releasing this power has a steep cost.  After the fire wanes, you experience the following:

• You gain 3 points of exhaustion.
• You are blinded for one hour.
• You lose all temporary hitpoints.  If this would reduce you to zero (or lower) HP, you retain 1 HP and fall unconscious.
• Roll a D100, and take on the corresponding madness effect from the long-term madness table.  This effect persists until you are no longer exhausted.

This ability may not be used again until 9 days have passed.