Who is Colonel Regan from Chains and what is their importance?

Colonel Regan is a Patriot colonel. Over the course of the novel, he promises Isabel her freedom if she will consent to spy on Eliu Lockton for him. He also gives her a password to be used for entry into the Patriot camp. Regan is the first person Isabel informs about Lockton's plan to assassinate General Washington. Regan does not, however, grant her freedom as promised.