Originally posted by Prometheus878
A legion has six medium and four heavy infantry dragons at its core, with half as many troops designated auxiliaries performing every other role (archers, slingers, light infantry, cavalry, etc.).
The additional four to six dragons of troops are skirmishers — light missile troops — who are drawn from the same sources as the legionnaires and are Imperial troops. Legionnaires and skirmishers are typically from the Blessed Isle, but sometimes incorporate recruits picked up while in the satrapies. Legionnaires and skirmishers are both part of the Imperial legions proper, as are a handful of specialist units. Auxiliaries stand outside of this framework; they're units of troops drawn from the satrapies, and they retain the organization, training, and leadership of their homelands. They are attached to Imperial armies but are not part of the legions.
(This will all be covered in The Realm