Ninja Mask

The thing you found was actually an enchnanted ninja mask. After trying it on you discovered it gave you enhanced speed, strength, agility and stealth. Some weeks after finding the mask you figured out by meditating you can unlock the skills, abilities, and knowledge of former wearers of the mask. The only skills or knowledge you have to contribute is your somewhat obsessive knowledge of heroes and villains. Soon after the discovery you figured out how to summon the abilities without a single thought. A few months later you are doing the superhero thing getting the attention of a hero, sort of the powers of the mask make you naturally avoid getting noticed. This is great for caching bad guys but it makes it hard to get credit in the hero world. One day after stopping some clueless thieves, you slip away unnoticed, again, and her a distinctably female voice say, "so your that ninja the crooks are talking about? Here I thought it was Batman working out some anger problems. Turn around slowly and come with me."