Hitpoints: All humans/humansized creatures have 50HP, even cavalry (you don't need to kill both horse and rider, only the rider, so no additional HP). Goblins have 40HP (more frail than humans), Grail Knights have 60HP (can take crippling wounds and fight on - for a little while!), Orcs have 70-90HP, depending on their size (they're pretty 'ard). Skeletons have 70HP, Zombies 80HP, as they will continue fighting even after loosing limbs. Vampires have 100HP. Monsters have 300-600HP, giants and the like 2000-5000HP. Lords and Heroes have ten times the HP they would have as a "normal unit", so human Heroes generally have 500HP, for example.
Ingame meaning: This is pretty obvious if you ever played any videogame, but when an individual "entity" (a warrior) goes down to 0HP, it dies. HP are lost by receiving damage. The sum of all soldiers' HP in a unit is displayed in-game as a unit's HP and this is the relevant factor for "damaged sustained" mali to morale. For this purpose, there is no difference between a unit of 200 entities having 100 entities die or a unit of 200 entities having each entity lose half its HP although all of them are still alive.

Armor: A light plate harness (like statetroops wear) grants 35 armor, with some more plates (greatswords, grave guard), it grants 50 armor. A full suit of plate armor grants 70. Chainmail grants 40 armor, with some plates on top it grants 60. Light armor (most Greenskins, Norse marauders) grants 30. Chaos Armor grants 90 or even 100 armor. Some beasts also have natural protection, dragons for instance get 60 armor from their skin. Riders on unarmored mounts lose 25% of their armor due to the vulnerability of their mount.
Ingame meaning: Half the armor value is always detracted from the damage an entity receives, the other half of the armor value is randomly detracted. A unit with 0 armor will always receive full damage, while a unit with 100 armor will receive between 50% and 0% of damage. A unit with 200 armor is immune to damage. Armor piercing damage however ignores this mechanic and always causes 100% damage.

Shields: Shields allow units to block 50 to 80% of projectiles coming at them from the front and also grant a 10-20 bonus to melee defence. Both obviously depends on the shield's size. Mounted warriors lose some blocking potential. Carrying a shield is somewhat encumbering and therefore causes -5 melee attack.
Ingame meaning: Blocking is a chance to completely ignore all non-artillery missile damage hitting a unit from the front. A unit with 50% block will ignore 50% of the projectiles hitting it frontally. This is different from missile resistance, which detracts from the damage dealt by individual hitting projectiles.

Leadership: Regard 50 as normal. Imperial statetroops have 60, knights have 80. Goblins have 30-40. For the undead, leadership represents not bravery but how stable their magical bonds are.
Ingame meaning: Another pretty obvious one, but here we go: A unit that falls below 0 leadership will break and run away. If it puts some distance between it and the enemy and somehow reaches a morale value of more than 0, it will rally after about 20 seconds. This might be due to a nearby Lord, no longer being in a melee it was losing, or no longer being under missile/artillery fire, etc.

Speed: Most humans have 32, which is the slowest running speed you can give them without negatively affecting animations. I did this for all units - infantry and monsters generally are the slowest they can be without looking weird. Cavalry, especially light cavalry, is much faster than infantry, which should be obvious, and flyers are much faster again.
Ingame meaning: ... Yeah, this is how fast an individual entity moves. Impact damage is hugely affected by this - the faster a unit, the more damage it causes by simply crashing into the enemy. See "Charge Bonus".

Melee Attack/Defence: This is tricky. Every unit has a base value here. 40/40 is normal for barely trained soldiers, well trained troops have 50/50, veterans have 60/60, elite warriors have 70/70. This base value is then modified as follows. Sitting on a horse makes defending yourself harder, so that’s -5MD, although it gives an offensive edge due to height, so that's +5MA. Chariots get the same effects as cavalry and an additional -10MD on top. Shields, as mentioned above, grant +10/+15/+20MD. Then, weapons play a huge role.
Ingame meaning: Melee Attack and Melee Defence determine the chance of an entity hitting another entity when it attacks. The defenders's Melee Defence is subtracted from the attacker's Melee Attack and the result is added to a base hit chance of 30%. A warrior with MA 50 attacking a warrior with MD 40 for example has a 50 - 40 + 30 = 40% chance of hitting. Minimum hit chance is 10%, maximum hit chance is 90%.

Weapons: Here’s a list of what weapons do, both in terms of modifying Melee Attack and Melee Defence and in terms of normal- and armour piercing damage.

• Axe: 15dmg, 3ap, -5MD. This is an unwieldy weapon, but it has some armour-piercing capability.
  
• Great Axe: 25dmg, 5ap, -5MD. It's a bigger axe!
  
• Hammer/Mace: 8dmg, 7ap, -5MD. This is an unwieldy weapon, but it is pretty decent at „piercing“ armour, as the armour does not actually have to be pierced in order to cause blunt trauma to the victim. Overall, however, it causes less severe wounds than an axe or a sword.
  
• Great Hammer: 13dmg, 12ap, -5MD. It's a bigger hammer!
  
• Sword: 20dmg, +5MA. A sword allows for fine maneuvers in combat, giving the bearer an edge over combatants with heavier arms. Damage potential, too, is fairly decent, but against armoured enemies, swordfighters will run into trouble.
  
• Great Sword: 30dmg, +5MA. It's a bigger sword!
  
• Spear: 15dmg, +5MA/+5MD, +5dmg vs large units. The weapon's length gives the wielder an edge in combat and allows the wielder to keep the enemy at a distance. Not a very strong weapon, though. Damage bonus against cavalry and monsters, as the weapons‘ reach allows for easy stabbing of riders and deep penetration into beasts‘ bodies, hurting vital organs.
  
• Spear (cavalry): 15dmg, +10MA. Using a spear from horseback grants decent reach, allowing for easier attacks on the footfolk below. Spears also grant a good charge bonus, being lances‘ little brothers.
  
• Pike: 15dmg, +10MA/+10MD, +10dmg vs large units. Even longer than a spear and operated with both hands, pikes give a big range advantage. A wall of these pikes is a daunting obstacle for both cavalry and monsters. A frontal charge on a unit of pikemen is useless, as this weapon grants immunity to cavalry-/monstercharges and a damage bonus against both. These stats consider pikemen to always be part of a formation - I am aware that in a duel, a pike is not particularly good.
  
• Halberd: 23dmg, 7ap, +5MA/-5MD, +5dmg vs large units. A halberd is badly balanced and defending oneself with it is very hard. It's damage potential is enourmous, though, and it's a good choice against armoured enemies. Damage bonus against cavalry and monsters due to the weapon's reach.
  
• Staff: 12dmg, +5MA/+5MD. A staff is not a very good weapon, although it's somewhat useful for self-defence.
  
• Lance: Cavalry using lances are treated as if carrying swords, because that's what they would usually switch to after the initial attack, but they get a huge mass bonus. Mass is a hidden stat that, along with speed, determines impact damage. Cavalry with lances absolutely obliterates anything in its path!
  
• Claws and Teeth: Xdmg, Xap, -5MA/-5MD. Damage here depends on the beast we’re talking about, but since they have a big range disadvantage and cannot parry or deflect attacks except with their own body parts, they get a malus to their combat ability.
  
• Dual-Wield: Xdmg, Xap, -5MA/-5MD. Dual wielding is quite difficult to get right, so it detracts from combat ability, but it doubles the attack speed. This is the theory at least. Since attack animations last for about 2,5 seconds, a slower attack speed is not possible, so now dual-wielders gain +50% weapon damage.

Normal fighters attack every 3 seconds, regardless of weapon. Dual-wielding increases this to an attack every 1,5 seconds (in theory).

Ranged Weapons: Here's ranged weapons explained.

• Bow: 200 range, 20sec reload, 20dmg, good at long range but generally inaccurate. Goblins cause less damage with bows (less drawing strength) and are more inaccurate. Orcs are even more inaccurate than their small counterparts, but their superior strength makes their bows more deadly when (if) they hit.
  
• Longbow (Wood Elves): 250 range, 20sec reload, 15dmg, 5AP, good at long range but generally inaccurate. Elite Elves are very precise, though, and fire pretty quickly. In between all-round bows and Bretonnian Longbows, as Elves don't generally have to deal with Knights at long range and thus don't built their bows for armour penetration.
  
• Longbow (Bretonnia): 250 range, 20sec reload, 12dmg, 8AP, good at long range but generally inaccurate. Along with Elven longbows, these have the highest range of all earthly weapons in the game. They can punch through armour, as they should, considering where they are used. Their firing rate and range make them superior in this regard even to crossbows.
  
• Crossbow: 200 range, 30sec reload, 10dmg, 10AP, poor at long range but a bit more precise than bows at short range. Also, crossbow troops are cheaper than their bow shooting counterparts in the campaign, to reflect them not needing nearly as much training to become proficient with their weapon.
  
• Handgun: 175 range, 45sec reload, 10dmg, 40AP, horrible at long range, increasingly "precise" at short distances. Almost completely ignores shields. Guns will kill you! Also, handgunner troops are relatively cheap in the campaign, due to how little practice it takes to learn gunnery compared to archery. Dwarven guns are a bit more precise at long range, since Dwarven engineers actually know what they are doing.
  
• Pistols: 100 range, 45sec reload, 20dmg, 30AP, horrible at medium range, not exactly precise even at short range. Shields are partly pierced.

Charge Bonus: The base value is 5, but some units have 10 or even 20 because they are especially ferocious on the charge (orcs, gors, slayers) or can exploit a sudden attack in another way (warhounds/wolves jumping on their prey for example).
Ingame meaning: This is a bonus to Melee Attack applied within the first 10 seconds of a unit charging. A unit will start "charging", which is a separate kind of movement besides walking, running and flying, at a bit of a distance, so this affects the first 1-2 attacks once a unit actually starts fighting.
The extreme "charge"-damage caused by cavalry units, especially with spears or lances, is actually "impact damage". Impact damage is determined by an entity's mass - a hidden stat - and an entity's speed at the moment of impact. Cavalry has more mass than infantry, and cavalry with spears gets an extra bonus to mass, while cavalry with lances gets an extra extra insane super-bonus.

Reload: This mostly hidden value used by ranged weapons is actually fairly important. The more experienced/better trained a unit is, the faster it can reload and thus the faster its rate of fire. Most units start out with 10 reload skill, which gives them 10% faster reload. This, combined with the fact that I put basic rates of fire at 110% of what they should be, means that basic units have normal rates of fire. More experienced units have 20, 30, or in the case of some elite elves, even 40 reload skill, which lets them shoot very quickly.

Ammo: (Cross-)Bowmen carry 10 arrows/bolts, gunners carry ammo for 4 salvoes, javelin troops carry 3 javelins and axe throwers carry 2 axes (plus the one they don't throw away). Mounted archers/gunners carry 50% more ammo (more capacity in saddle pouches), chariots twice the normal amount of ammo (lots of spare room). Historically, ranged troops carried far more ammo, but for balancing's sake, I restricted this a lot.

Experience: Units get noticeable boni from their experience levels now. Leadership, Melee Attack/Defence and Reload Skill can increase as much as 30% through experience!

Some Races are obviously physically very different from humans and receive boni and mali to their stats.
Dwarves: Due to their height disadvantage, they get -5MA/-5MD. Otherwise, they're comparable to humans.
Goblins: Like Dwarves, they get -5MA/-5MD due to their height. They also cause 10% less damage due to their inferior strength.
Orcs, Gors, Vampires: These races cause 10% more damage due to their superior strength.
Bigger Orcs, Chaos Warriors: These brutal mountains of flesh cause 20% more damage.
Damsels, Necromancers: They are not exactly another race, but since they're weak women/old men, they cause 10% less damage.

Monstrous Units mostly do AoE damage, which is quite a complicated affair due to lots of hidden stats. Very basically, Trolls, Minotaurs, Crypt Horrors and comparable units cause twice the damage they would with human strength, while Giants etc cause four times that damage. Due to the way AoE damage works, you'd have to look into the files to see proof for this, as the in-game stats for AoE weapons will not properly reflect this. Monstrous Units attack every 4 seconds.

Lords and Heroes get a multiplier of 5 on their weapon damage, which makes them especially good at killing each other (against most normal enemies, it's mostly overkill). Monstrous heroes get a multiplier of 2,5 on their weapon damage, because everything above that would be too insane.