The Lyrian Army forms a professional military force of Lyria and Rivia, led by its monarch and select knighthood. It's a professional and valiant force, with quality full-plate armor and strong horses for its knights as well as adequate training and equipment for regulars though, in hard times, they recruit bandits, renegades, and other outlaws from Angren and Riverdell to expand its might as much as possible and start guerilla war in Dol Angra forests.
The army also doesn't refrain from taking in dwarves and donning them in white tunics decorated with red lozenges of Rivia. However probably the most notorious regiments consist of Lyrian Arbalests, who shot better than any other.
When in 1267 the Second Nilfgaard War broke out, Queen Meve's forces were first to cross swords with Nilfgaardian Army at Glevitzingen, Scala, and Spalla. In the beginning, the kingdoms of Aedirn and Lyria only managed to mobilize three thousand horse and ten thousand foot, of which one fifth had already been blockaded in the first days of the invasion, cut off in its forts and strongholds. Part of the remaining army had to withdraw to protect its flanks, threatened by far-reaching raids by light cavalry and diversionary strikes by Scoia'tael units. The remaining five or six thousand soldiers, including no more than twelve hundred knights, was beaten in Aldersberg.
Though Demavend was forced to flee to Redania, Queen Meve wasted no time and assembled a new partisan army, bravely leading partisans from the whole area as the "White Queen" into clashes like Battle for the Bridge on the Yaruga. After the Battle of Brenna, when the war turned against Nilfgaardian Empire her army got to liberate the domains along with Kaedweni Army and restored forces of Aedirn.