You were raised by Myconids, who are naturally distrustful of humans. You appeared in one of their circles as a child, whether you fell into the Underdark or were dropped into it. Maybe the Myconids believed you to be a symbol from their gods, or perhaps you were found by a Myconid Sprout and raised as a sibling. The Myconids taught you their ways, and you grew into a simple life of work and sleep. 

Skill Proficiencies: nature, survival

Tool Proficiencies:  Alchemist's Supplies, Herbalism Kit

Equipment: Your choice of an Alchemist's Supplies or a Herbalism Kit, a rock that is very special to you, Clothes, Common made out of foraged materials, and a handmade pouch containing herbs and other plants worth 10 gp.