Jim Nelson

Jim Nelson (aka "Shadow Shepherd") is regarded as the second best neurosurgeon at Seattle Grace Hospital.

Personality
Nelson was not very well known or associated with. Webber called him James and when Nelson asked Mark if he'd like to get a drink, Mark declined. Also, when Mark introduced himself beforehand, he failed to realize that he had already met him three times prior to the occasion.

Career
Dr. Nelson was the interim chief of neurosurgery before Derek was hired.

According to Callie, he is a good surgeon, publishes a lot of research, but because he isn't Shepherd and Richard's golden boy, he falls to the sidelines frequently, so much so that Richard does not actually consider him for any of Derek's surgeries when Derek "leaves". Mark has also failed to notice him in the time he's been working at Seattle Grace, despite Jim working there for more than 10 years.