This mod makes combat more realistic. Armor values are based on experimental data. Armored units are more resistant to damage depending on weapon type used vs armor. Each weapon type has different effect vs armor. All units defend themselves more, units with shields actually use the shields. All projectiles now cause damage based on their kinetic energy. Kinetic energy of projectiles is result of simulation based on real life experimental data. All battles are significantly longer now. Damage of horse charge is physics based, couched lancing is scientifically accurate. AI armies use more tactics. Spears are buffed in melee in comparison to vanilla.

Announcement: If you care about future of bannerlord Bannerlord please vote and comment in this poll:https://forums.taleworlds.com/index.php?threads/do-you-want-more-complex-features-such-as-proper-formation-behaviour-in-bannerlord.447006/

Features:

• The mod contains multiple modules and settings which can be toggled on / off in the game main menu.

• Combat module in a nutshell:  

1. In the base game there are three types of damage: pierce, cut and blunt. In this mod each weapon type has unique armor penetrating properties, which results in more realistic experience. For example sword is poor at cutting heavy armor, axe is better at this and mace punches through the best. Values for weapon modifiers and few others are all configurable in config file (edit config file in the user/documents). 
2. Projectile speed is simulating real life physics. Bows and crossbows have their draw weight displayed as missile speed stat. Actual speed of projectile is based on weapon type, draw weight (missile speed), missile weight and many other factors such as draw length and efficiency of energy transfer from work to stored energy, then from stored energy to actual projectile. Crossbows, longbows and composite recurve bows (mostly horse archer bows) have each unique simulation based on real life experimental evidence. For example composite bows are more efficient than longbow of same poundage and they are more efficient with lower weight arrows. Generally higher weight arrows are more energy efficient than lower weight arrows (damage) but heavier projectiles are slower and therefore have shorter range just like in real life. 
3. Javelins and throwing axes are good against light-medium armored enemies and they can destroy shields now. Arrows now also deal reasonable damage to shields. Speed of the throw is based on weight of throwable - smaller = faster, larger = slower. Heavy projectiles such as javelins profit from bonus speed more than lighter projectiles such as arrows.
4. Shields now have realistic hitboxes (in vanilla their collision hitbox is much bigger then their visual size). This means arrow volleys or well aimed shots can now go around shield or even pass through shieldwall (hitting arms, heads or legs that are sticking out). 
5. Couched lances now deal kinetic energy based damage (heavier and faster is better). Stabbing with spear from horseback will generally cause less damage than couching at high speed as was the case historically. Couchable lances are held in last third of the shaft and are longer to reflect their purpose of outranging spearmen and regular horsement on the other side they are less wieldy and pretty much useless outside of charging. If blow from couched lance is particularly powerfull, it can dehorse enemy horseman. Similarly, bracing with heavy polearm like pike can dehorse rider too.
6. Horse charge cause physics based damage, horse receives some damage when it charges too.
7. All melee damage was changed to reflect kinetic energy from experimental test. One handed weapons generally deal 60-120 damage while two handers are in range of 100-180 depending on weapon type and its length.
8. All armors were rebalanced based on their material and how well they cover bodies of their wearers according to scientific literature and experimental tests.
9. Armors can full block incoming attacks if they are strong enough. In such case only a small portion of the damage will be transferred into blunt trauma damage. You can achieve higher damage by increasing relative speed of the projectiles (for example by shooting from running horse in direction of the enemy) or by increasing your character skill with the weapon. So just like in real life.
10. Hitboxes were reworked, to reflect actual armor coverage of armor pieces: Head hitbox = 100 % of helmet armor, neck hitbox = 60 % of helmet armor, chest and abdomen hitbox = 100 % of "body armor" on your chestpiece, shoulder (breasts, shoulders and upper half of arm in game) = 100% of armor on your shoulder piece and 100% of your "arm armor" on your chestpiece, hand hitbox (from hand to elbow) = 100 % of armor on your gloves, leg hitbox = 50 % of your boot armor and 50 % of your "leg armor" from your chestpiece.
11. Melee weapons have weights and speed closer to the historical weapons (they are lighter and faster) than in vanilla.
12. Two handed swords can be used as bastards with both hands and one hand (since zweihanders are real 2h-only swords and they are difinitelly not present in Bannerlord).
13. Two handed polearms, two handed axes and two handed maces will stagger enemy when they are parried by melee weapons or blocked by shields from incorrect angle, this should help with their shock capabilities.
14. Axes will do more damage to shields.
15. Blunt damage can now kill just like pierce and cut damage.
16. Skill  of the warrior is much more important than weapon it self. Damage, speed and handling of weapon is significantly affected by the weapon skill, for now applies to melee weapons. Damage stat of the melee weapon have reduced effect.
17. Damage with couched lance is strongly dependent on skill. Ballistic damage of the lance is the same no matter the skill, but weight added to the lance by the rider is skill dependent.
18. Melee weapon skill scaling: swords - low base damage, highest skill scaling; axes - moderate base damage, moderate skill sclaing; polearm - high base pierce damage, low pierce skill scaling, moderate base cut damage, moderate cut damage scaling with weapon skill, couched lance low base damage at moderate speed, high scaling of damage at moderate speed with skill; maces - highest base armor piercing damage, lowest skill scaling.
19. Throwing weapon skill scaling: Strength (and speed) of throw is based primarely on skill, if you want to deal lot of damage with javelin (or throwing axe) and if you want to throw heavy javelins you need high throwing skill. 10 (5 in case of axe) bonus m/s speed is added to throwing weapons, this speed is not added to the final calculation of damage, this is to make AI throw from further range (just in case you were wandering why you throw like olympic athlete) but the kinetic energy is still correct (so 35 m/s javelin have kinetic energy of 25 m/s javelin).
20. Bow and crossbow reload rate: Bow and crossbow reload rate was changed to historically accurate speeds relevant for war equipment - three setting are available, realistic (slow), semi-realistic (moderate), vanilla (fast). This setting is applied only to player, AI will always use realistic reload.
21. Bow drawing speed: When you unlock new bow with your skill, it will have draw speed of roughly 3 seconds, you can increase this speed further by training with the bow (skill scaling), when you have 50 more skill than is required to unlock the bow you will reach 2 seconds drawing speed, your drawing speed will further improve with more skill past that point.
22. Units have correct gear for their tier. 
23. Each nation have specific strenght and minor clans are very specialized.
24. Spears will deal decent damage during entire animation including beginning of it, spears will not get stucked to allies when used in tight formation, inspired by now defunct fix the spears dude.
25. Due to changes to stats, prices of items have been reworked. You can tweak them in the config.
26. Shield on back was reworked, it can now stop all damage if the shield is hit. Kite shields, khuzait round shields and pavises are worn on shoulder instead of back when they are not equipped in hand, this results in protection when bracing and reloading crossbows, this can be adjusted in game menu.
27. Horse harnesses will now have head armor, neck armor (arm), frontal body armor (body armor) and rear body armor (leg). Some harnesses are going to have good frontal but poor rear protection.
28. Arrows and bolts use their real meshes instead of wooden bars, this can be reverted in game menu if you prefer original look or have performance issues since mod patch 2.2.0.
29. Parrying, fighting in arenas and training area will give proper xp now. Hitting and parrying enemies that have higher level than you will give bonus xp, this applies to AI leveling too.
30. If you want to understand more about weapon damage in RBM please see articles section.
31. Greased and hardened arrows and bolts added to the game (this items will turn into trash if uninstall the mod, so no crashing).
32. Partial penetration is now possible with all piercing attacks but arrows and bolts. This means that blade can partially penetrate the armor (splitting single ring, making small hole in the armor) for up to 15 damage with relative ease but any damage above that requires much more power to fully penetrate.
33. Speed shooting is available both to player and the AI (disabled in version for 1.8.1, works in version for 1.9.0). You need to have 70 more skill than is the bow difficulty to unlock it.
34. When targeting reticle (crosshair) is disabled your shot angle will be increased by roughly 5 degrees just like IRL with most of archery anchor points. This improves aiming at longer distances.

• AI module in a nutshell: 

1. Esentially armies will use some tactic (instead of Charge) when in battle, in vanilla army leader needs to have like 150-200 tactics skill for this to happen, with RBM tactics will always happen. 
2. Also some of the vanilla tactics are literally broken or not function properly so we disabled these (circle of sucide when facing horse archers, hold the "choke point" in shield wall until you get surrounded and murdered and so on). 
3. We also upgraded the remaining tactics. For example archers will often stand behind infantry line in much wider formation than infantry so they can flank while having some protection. When army holds the high ground it will actually do few steps forward so archers can properly shoot and infantry in front of them does not obscure vision, in vanilla archers actually stood behind the hill and they could not shoot while infantry stood on the hill. 
4. Horse skirmishers (javelins) will circle around enemy formation and throw all their javelins (just like horse archers) and only after that they will charge, in vanilla they just charge through formation and sometimes throw javelins. 
5. Horse archers will circle around from safe distance so they wont just bump into enemy infantry all the time. They will also charge close (which adds speed to their arrows) and the turn arround (hit and run).
6. Cavalry will used their couched lances properly, it will charge then disengage to the distance and then charge again instead of getting stuck in the fight. 
7. When archers are in range but for some reason they cannot shoot, for example because of hill they will do few steps forward, they will keep doing this until most of them starts shooting. 
8. Adden brand new tactics to the AI - Embolon to Empire, Skirmisher flank to Aserai, Archer flank to Battania and Shock Trooper flank to Sturgia.
9. Soldiers with shields will block arrows more often and when under heavy fire entire formation will raise their shields. 
10. Units block and parry much more than in vanilla which makes the combat bit longer, this depends on skill of soldier and combat difficulty setting. 
11. Infantry will properly throw their javelins both when defending and attacking.
12. Defenders will now properly hold the gate when it is broken and the wall when it is breached.
13. Units with two handed polearms will try to keep proper distance and as result will fight from second line of formation more often.
14. Improved melee formations in field battles. Soldiers in formations will behave more like people, they will poke each other, attack and retreat instead of attacking like robots that dont care about dying. Phalanx, pikewall, shieldwall is more viable and battles are longer.
15. Spear and Pike infantry will hold their ground and brace when charged by cavalry.
16. Skirmisher infantry (troops with more than 2 javelins) will now try to skirmish when they are dominant unit in formation.
17. Posture system added to the game. Your posture bar is shown below your health bar. Enemy name, health and posture is shown in the top middle part of your screen (below balance of power bar). You lose some posture when you attack, you lose more posture when you defend from enemy attack, perfectly timing of your block / parry significantly reduces posture damage which you receive and causes lot of posture damage to the attacker, blocking into incorrect side with the shield or holding parry for a long time before actual attack will result in more posture damage than perfectly timed block or parry. Posture regenerates over time. When soldiers posture fully depletes he will recieve some adverse effect (read below) and will regen half of his posture back (so you can turn the tide of battle evne if you are loosing at first).
18. If you attack enemy with shield that dont have enough posture to block he will be either knocked back (if he times his block in correct position properly) or knocked down (if the enemy does not block in correct position). However if you perfect parry / perfect block attacker that has low posture and is carrying a shield, this attacker will be knocked down.
19. If you attack enemy without shield that dont have enough posture to parry he will be knocked back and will receive crush through. If you perfect parry someone that has low posture, you will knock him down and cause crush through.
20. Heavier weapons (such as maces) are better at dealing posture damage but receive more posture damage when they parry in comparison to more nimble weapons (such as swords). 2 handed weapons are generally better for parrying thna one handed (they reflect more posture damage when they perfect parry). 2 handed swords are best for dueling.
21. You character weapon skills and athletics (or riding when on mount) affects you posture damage and posture regen.
22. You can disable posture system or its GUI in the mod options.
23. Reinforcements will come from edge of the battlefield instead of teleporting into static point that is mostly behind default spawning position. This means you can actually use the new deployment system and you will not screw yourself in the process.
24. Super speed feature was added to the module (original mod is no longer functional) press ctrl + v to increase game speed (or return in back to normal).
25. Improvements to defender postions on some maps. So far: Ab Comer castle, Veron castle, Zeonica, Vostrum, Verescand castle, Varnovapol, Thractorae, Seanon, Jogurys, Lageta and Takor castle. More to come in future patches.

• Arena Module:

1. Enemies in arena will be on your tier level. Player tier is calculated from player level and gear, whichever of these two values is higher will be chosen.
2. Rewards are 1 tier higher than tier of the tournament, so player should be able to upgrade by fighting in arenas. 
3. Renown reward for fighting in arena is increased as well (higher tier = more renown).
4. Melee weapons and shields will be randomized and of appropriate tier and culture. Bows and arrows will scale with arena tier aswell.
5. Since tournament is fair now it is good way to train and learn how to fight with Combat and AI module. Combat module also enables normal XP gain in arenas.
6. 1v1 fights will be sometimes fought with shields, sometimes with just 1 handed weapons instead.

Also all of this aplies to AI, player can activate all the tactics related stuff by "delegating command to sergeants" with either entire army or specific unit formation (proper charging with cav and proper distance with horse archers work with "Charge" command as well).

If you are interested in tweaking some of the mod settings go to users/"user name"/documents/Mount and Blade II Bannerlord/configs, you will find RBM combat and AI config folders there. These changes will be remembered even after new patch.
Our optional mods (in files section below main mod files), both of these mods also work as standalone mods:

• VolunteersUpTier - at the moment archived (only up to 1.7.2) - this optional mod changes starting tier of volunteers that appear in settlements. This tier is configurable with config.xml in mod files. This submod aims to up the difficulty in campaign mode. AI lords in campaign fight battles all the time and they often loose entire armies, so then they fill up their whole armies with recruits. Player is much better at conserving units and often has elite armies. As a result battles in campaign are often extremly one sided because of this. This mod serves as hotfix for this problem as AI lords armies will be closer to player's and battles should be a more challenging. In future we hope there will be some other way to fix this problem ( better soldiers from prosperity, training soldiers in castles and so on ). Works also as standalone.
• Lord Retinue Uptier - this optional mod improves the armies (AKA retinues) that are spawned with AI lords (not your companions) when they are spawned / released / ransomed / escape from captivity. This will put more good units into game and also make battles vs AI armies harder.

Installation: RBM is installed like majority of other mods, AKA put its folder into modules folder. VolunteersUpTier and Lord Retinue Uptier are again standard mod installation.
Recommended mods:

• More income - from one of the authors of RBM, increases price of trade goods, which
increases income from workshops, manual trade and hopefully caravans. Good if you want to focus more on leading armies and less on griding money.

• RTS camera - very good mod, aside from the camera stuff also allows you to play as
one of your soldiers after dying and increase or slow down the game speed. Original mod is again updated for the current game.
• Diplomacy - makes strategy map part of the game better, alliances, non-aggression pacts, factions within kingdoms et

Recommended mods to try out with RBM:

• De Re Militari at Mount & Blade II: Bannerlord Nexus - Mods and community - unit overhaul that is fully compatible with RBM features, infantry is generally less armored in this mod.
• Auto Resolve Rebalanced - highly recommended, it makes autoresolve battles much closer to results from actual battles, which helps AI siege. Recent changes to garrison growth made in vanilla makes it very hard to take castle in autoresolve.

Check whether these mods are supported in current version of the game before installing them.

Warning: Most mods that modify spitems.xml (for example some armor mods) do it in a very clunky way and change the entire file, as a result balance of our mod is broken by these mods (for example bows are turned into ballistas :D). If you want to avoid these issues try loading our mod last or try disabling the other mods.

Compatibility:
Please note that any mod that affects stats of bows, crossbows, arrows and bolts is not compatible with the combat module.
Any mod that changes how damage formula of arrows or melee weapons works is also not compatible with combat module.
Other mods should be compatible.

Spear Rework is conflicting with combat module and may be cause of crashes.
ANY mod that adds armors and/or weapons is NOT compatible with Combat modules unless there is a RBM patch for it.
Raise your banner mod is in conflict with AI module, and breaks AI behaviors.

Special thanks to Mod Template for Visual Studio mod which allowed us to do this mod and Another Armor Damage mod which helped us understand programming in Bannerlord.

Source files are included. For finding how code works in original game i highly recommend program called ILSpy. You can use it to browse game's .dll files and see original methods and callbacks.

Installation: 
Put our mods in modules folder just as any other mod, run DLL activator. We recommend manually installing the mods, there seem to be problems such as crashes for some people when using vortex.

Troubleshooting:
Before posting your problem or question please check the sticky posts, you may find solution to your problem or answer to your question there.

If you want to support us you can do so here: https://www.buymeacoffee.com/RBM.Team

Source code: https://github.com/Fellow93/RealisticBattleProject

Discord: https://discord.gg/59rMXRJ