No, he's not schizophrenic! The premise of the show is that when the Sheriff of Nottingham's wife is killed by King John’s men and nobody is brought to justice, he launches a one-man war against the Crown. By day, he remains the loyal servant of the King, but by night he becomes Robin Hood. Using the intelligence he gains from his office he then attacks the King where it hurts the most, his coffers. In traditional Robin Hood style, he gives the riches to the poor and in doing so helps start a rebellion that will change England forever.
Traditionally the Sheriff was always the antagonist, but it seems in this re-imagining he's the one we will be rooting for. It sounds like quite a novel idea and if executed correctly could be quite interesting. Here's hoping they do it right!
Source : Deadline
