Dr. Fauna

From publisher blurb:

This is a new collectible RPG in a Golden Age Superheroes vein: to play, you just need any set of the playbooks, with at least one per player. Each playbook gives you a pre-made character and all the rules needed to play them or to run the game for others.

From Introduction:

Exclusive story: the Secret Origin of...Dr. Fauna!
Charles Channing, a man of learning blackmailed into parting with his secrets when hoodlums abducted his wife. Unable to let his miraculous potion fall into the wrong hands, he took it himself and fought the whole gang single-handed! It was too late for his beloved wife though, who died in his arms, leaving him with a thirst for vengeance!