Army

Introduction
This is another aspect of the game mechanics that adds complexity. The composition of your army is represented by 2 stats: These stats determine which rewards you receive after the battle with the horde in Chapter 2 as well as playing a large role in determining the outcome of the Battle of Yhilin at the start of Chapter 3.
 * Size: A representation of how many people are in it.
 * Quality: How disciplined and well trained they are.

Possible Recruits Pre-Horde
So far, it's possible to avoid getting any army but Orcent's band, and although the losses against the Orcs are heavy, that doesn't mean a Game Over but the reward list from the Horde Battle is minimal (and Carina's soldiers die.) It also results in suboptimal outcomes and negative consequences to the Battle of Yhilin.

When you recruit Orcent: When you hire mercenaries in the Outskirts of Ari-Yhilina: If you invest in Premium Steel: If you invest in Mine Processing: When you recruit the Succubi in the tower near Stineford: If you recruit the group at Withered Mountain: If you recovered Stark's Head: If you spared The Impaler: MAXIMUM VALUES FOR INCUBUS KING'S ABORTIVE INVASION:
 * You start with an army of Size 3 and Quality 1.
 * When you return to the farm (during Chapter 1), Simon can talk to a recalcitrant orc in the storehouse. If Simon attempts to dominate the orc and his level is 12 or higher, you get +1 Quality. If Simon's level is below 12 or he chooses to fight the orc, you get -1 Size and +1 Quality.
 * When you return to the farm (during Chapter 1), Simon can talk to a recalcitrant orc in the farmhouse. If Simon attempts to dominate the orc and his level is 14 or higher, he can cow the orc for no change in stats. If Simon's level is below 14 or he chooses to fight the orc, you get -1 Size.
 * At the start of Chapter 3, you get +10 Size and +3 Quality.
 * Hiring the Iron Cudgel: +2 Size +1 Quality.
 * Hiring the Dusty Horde: +5 Size.
 * Hiring AriGarda: +2 Size +3 Quality.
 * +1 Size, +1 Quality applied at the start of Chapter 3.
 * +1 Size, +1 Quality applied at the start of Chapter 3.
 * +2 Size, +1 Quality if you talked to their leader during Chapter 1.
 * +1 Size, +1 Quality if you did not talk to their leader during Chapter 1.
 * +3 Size at the start of Chapter 3.
 * +3 Size, +1 Quality if you convince 29 or more to join you.
 * +2 Size if you convince 15-28 to join you.
 * +3 Size at the start of Chapter 3.
 * You get a synergy bonus for the passes battle.
 * +1 Quality at the start of Chapter 3.
 * No effect on Army rating, but you get a synergy bonus for the passes battle.
 * Participates in Battle of Yhilin, yielding different results based on scenario.
 * Size = 17
 * Quality = 8

Impending Horde Battle
The amount of Sx is determined by army size, the quality of the items is determined by army quality.

The results vary with your army strength. Generally speaking, if you do the maximum to reinforce you inhuman troops without getting mercenaries, you get 3000 Sx and army quality will be 4. If you hire Iron Cudgel, quality will grow up to 5, and Carina's men will survive. If you hire AriGarda quality will be even bigger so you get maximum reward. No sure, but for getting 5000 Sx you will probably need two mercenary companys.
 * Orcent will give you a variable amount of money in function of the size + hidden variable (see below) of your army, expressed as a number n:
 * n >= 5: 1000 Sx
 * n >= 8: 2000 Sx
 * n >= 10: 3000 Sx
 * n >= 15: 5000 Sx
 * The succubi village will give you various gear based on army quality:
 * 2 quality will net you a Steel Armor.
 * 3 will get you a Full Plate instead.
 * 4 will get you a Shining Sword instead.
 * 5 will get you the Full Plate and Shining Sword.
 * 6 or above and you win all three.
 * Carina's men will be saved by any mercenary company and will give you a Shining Armor. No effect on Carina affection or hidden Religion variable.

Synergy bonus
A hidden synergy variable is calculated. It is added to your army size to determine Sx earned from the battle (see above), and a total of 12 from size + quality + synergy is needed for the Orcent Orgy scene.

What affects synergy: Efficiency in the preceding section of Chapter 2 affects several hidden checks, but none related to this battle.
 * Having both the AriGarda and Iron Cudgel will give you +1
 * Having both the AriGarda and Dusty Horde give you -1 (stacks with above)
 * Having both the Withered Mountain Troops and the Succubi Tower will give +1, but only if you talk with them outside the dark tower to trigger their scene.
 * Having both Orcent and Impaler will give +1, but only if you watch their cutscene outside the Abandoned Fortress.
 * Having Orcent and Stark's head will give +1, but to get this you have to talk to Orcent at least twice outside the tower in order to show it to him.

Megail's Route
If you invest in the Eustrin suppler:
 * +1 Size, +1 Quality applied at the start of Chapter 3.

After the Reunion
If you asked Robin to research orcs: If you invest in mercenaries here, there are a few changes: If you purchased mercenary services before, you'll pay some upkeep to keep them on when you talk to Megail, but their bonuses are unchanged.
 * +1 Size, +1 Quality applied at the start of Chapter 3.
 * AriGarda is no longer available for your army, but you can pay them 10k ProN to align with House Rose, otherwise they end up signing with House Adamant.
 * Iron Cudgel has declined in numbers since you didn't hire them before, so you only get +1 size, +1 quality. They're also more desperate, so they'll sign on for only 5k ProN.
 * Dusty Horde is unchanged, but cheaper - 10k ProN..

Depending on the Outcome of the Orc Extermination Motion:
 * If the motion failed, you get +2 Size and +2 Quality at the start of Chapter 3.
 * If the motion passed, you get -1 Size at the start of Chapter 3.

Battle of Yhilin
If you have come here from the Battle of Yhilin Guide, the values listed as "start of Chapter 3" are the same ones listed in the Army Recalculation section of that guide, so if you are trying to track your army's stats, be wary of reapplying the same modifications. For the Battle of Yhilin, only your nonhuman forces apply to your Army scores, so subtract any increases you received from hiring mercenaries.

MAXIMUM VALUES FOR BATTLE OF YHILIN:
 * Size = 30
 * Quality = 14

There are many modifications that will happen to your army's scores during the Battle of Yhilin. There is no simple way to reflect those changes here. If you don't mind spoilers and looking under the hood of the game, visit the Yhilin Battle Guide to track the attrition suffered by your army during the battle.