Admiral
An Admiral, in a Total War game, is the character who leads a fleet. He is similar to a captain in that he is seemingly faceless, identical to other admirals. Unlike a captain, however, an admiral may not be adopted into your family, however high his rating becomes.
Only 3 attributes have an effect on an admiral: NavalCommand, LineOfSight and MovementPoints. NavalCommand effects his fighting ability, LineOfSight affects how far the fleet can see and MovementPoints affects how far a fleet can move.
Note: In RTW if an admiral has acquired any ancillaries (retinue members) or any points towards a trait (not necessarily a full level) the admiral cannot be merged with another admiral that also has ancillaries or trait points. The same applies for M2TW, except that admirals can only gain traits.