What is Satoshi Nakamoto?

Satoshi Nakamoto is the pseudonymous individual or group responsible for creating the Bitcoin protocol. Satoshi Nakamoto famously published the Bitcoin whitepaper in October 2008 and mined the first 'genesis' block on the Bitcoin network in January 2009. In April 2011, Satoshi Nakamoto posted on an online forum saying that he had "moved on to other things" and disappeared completely from the blockchain community. Since then, the true identity of Nakamoto has remained unknown, although there are a variety of unproven theories which claim to have unraveled the mystery of this individual/group.