Aedirnian Army

Lyria with Aedirn issued about 13 thousand soldiers, including 3 thousand of calvalry. In the early days of the invasion 1/5 of these forces was cut off in the forts and fortresses.

Main article: Aedirn Special Forces
The Kingdom of Aedirn indeed had Special Forces that were a group created by king Demawend III of Aedirn to fight the Scoia'tael. Their weapons of choice were black, gold and red bows, but they carried other weapons as well. They were leaded by Rayla.

2nd Nilfgaard-Northern War (novels)
Part of the remaining troops had been withdrawn to defend the wing against light cavalry and Scoia'tael. The remaining army, about 6 thousand. 1,200 soldiers knights, was beaten in Aldersberg. The current state of the armed forces Lyria and Rivia may be determined at approx. 8 thousand. infantrymen who fought as a diversionary force during the last war with Nilfgaard. King Demawend III was also known as tactical genius.

Wars for Pontar Valley (novels - The Witcher 2)
While Empire of Nilfgaard and Kingdom of Kaedwen made pact of dividing of Aedirn, some troops of Demawend III refuge in Hagge, where they were backed by the deposits of armies of Temeria and Redania. This part of the troops took part in the battle of Brenna and Aldersberg.

In The Witcher 2, Aedirn army is defeated by the peasantry. In Vergen under comand of Saskia is approx. 200 dwarves, half a thousand peasants, 53 knights and 200 military and 100 Scoia'tael.

3rd Nilfgaard-Nordling War (The Witcher 3)
During the 3rd Nilfgaard-Nordling War, Aedirn is conquered by Nilfgaard and army crushed very quickly.