The most important investor you've never heard of refuses to be on Forbes' Midas List.

Napoleon Ta—a former poker player who puts himself through college with winnings—is arguably Founders Fund's most influential investor after Thiel himself. He runs their growth practice and is "majorly, majorly responsible for the firm's gains and returns."

Ta keeps such a low profile that this might be the first time his work has been shared in-depth by a colleague…