The Eiras are Goidilic chiefs and their retainers. Their experience, high morale, and strength of their attacks make them valuable, and their presence inspires others to fight.
The Eiras (Ar-es; "Nobles") are Goidilic chiefs and their retainers. Equipped better than other Goidilic soldiers, they're also generally far more experienced; this accounts for their position as retainers of a chief. There are literally hundreds of chiefs though, beholden to chieftans, who are beholden to lesser kings, beholden to a high king. They carry throwing spears and longer iron swords than other swordsmen would often have a chance to carry. Their experience, high morale, and strength of their attacks make them valuable, and their presence inspires others to fight.
Historically, early Ibero-Celtic Ireland was populated by numerous tribes with an overking, from which spawned the seat of the high king that fell into constant contest by the time Rome fell, and the sub-kingdoms of Ireland were rendered into warring splinters. However, despite the varying periods of relative stability with a kind of warring states period, the Goidils always relied on a tribal model, with each family being headed by an elected chief, who acted as the tribe's spokesman to the mounting tiers of officials. Such men would have private guards and champions that would also fight as heavy infantrymen. While the armaments of such soldiers may have changed over time, their general purpose would not have changed. In this period, the Goidils were rather prolific traders with most western powers, and even reportedly bought, among other things, armor from Carthage, which they would then modify slightly to fit their needs.