Epones Lancearos are the primary shock cavalry unit of the Lusitanian muster, and constitute well-armoured men on horseback bearing the Lancearos, a rather long spear with a very large head. While this makes them vulnerable if rushed by sword cavalry, Epones Lancearos can function as well as any form of shock cavalry, especially if used against lightly armoured targets. Light infantry, such as archers and spear levy don't stand a chance if they face the awesome charge of armoured Lusitanian cavalrymen bearing broad-headed long lances.
Even so, Epones Lancearos are not invincible. If you use them against other cavalry units, such as those of the Romans, the odds are that you will be able to rout them, but were they to face more serious resistance in the form of Eastern cataphracts, they are bound to suffer immense losses. Even medium and heavy skirmisher cavalry en masse can break a charge of Epones Lancearos — by first outpacing them, then by spearing them from the flanks. Plus, the Celtiberians also have many other prized cavalry units who are able to take on the Epones Lanceari at their own game,meaning that without the support of more determined units, your prized Lancearos spearhead might well be whittled down to nothing. Thus, the Epones Lancearos are best kept in the early game, backed up by your other units, particularly the Curisi and Scutanann cavalry, but once your opponent begins to train heavy cavalry of their own, you should consider raising the elite Catuvaram lancers, and the Arjos Epones melee cavalry instead.