In the campmaps folder:

Medieval - Total War\campmap\names

there is a file default_heroes.txt

it has Robin hood under rebels names.

"Robin", "of Locksley", 1191, 3, 1, 3, 2, 6, merciful1, GENERAL, ID_MERCIA, 4 //Robin Hood!

it is defined as a General instead of an agent (e.g EMISSARY)

in the "Medieval - Total War\campmap\pieces\Agents"

Robin hood is actually an agent/piece. the images for picking up and moving him are in this folder

Never mind. i used him to create a new assassin unit