Ancient Warrior

You are much older than your enemies would guess. Your long experience in battle has wisened you, but prolonged combat exhausts you. 

• You gain proficiency in Wisdom saving throws.
• While in combat, you have advantage on Wisdom-based skill checks and Wisdom saving throws.
• Once per round of combat you can add your Wisdom modifier to an attack roll and subsequent damage roll.
• You take 1 temporary point of exhaustion every 4 rounds of combat; all but one of these points are removed after a short rest.

Requires an age of your race's average lifespan or older.