You may try my method: Gradually killing the enemy over several assaults using ranged troops.
I do this because I dont want any of my troops to be killed.
1) Party set up:
About 300+ Elite Skirmishers/Archers. I personally prefer Pictish Elite Skirmishers (crossbowmen), but others can be okay.
Each of your companions has 3 or even 4 shields.
Some Norse Huscarls (optional).
(leave all other troops somewhere else like troop quarter)
Do not let any other lords join the assaults, even if you can command their troops in battle, they are not good for your plan because they lower the number of elite troops actually join the battles.
2) Assaults
- In the beginning of the assault, tell all of your troops to hold fire and stay far from the enemy.
- Personally use your character to bait the enemy to throw javelins and throwing spears at you. At that range, you can move around to evade the most projectiles, block which you couldn't evade with your shield(s). Remember to get back and hide when your stamina is low. Repeat until your shield(s) break and you feel that you shouldn't risk your own character anymore.
- Continue with your companions. Don't worry, they won't die and they have many shields. Tell them to spread out and swing left and right (use "hold this position" to make them move, with either holding F1 or click on map). The enemy (as defenders) get bonus precision, but seem to aim the the target's position when they start throwing. Therefore, moving around may help evading a lot.
- After that, the enemy should run out of projectiles. It's safe for your elite skirmishers to get very close and shoot the enemy. Note that you should only tell them to "Fire at will" after all of them get in position (close to the wall and "stand closer" (F2 F4) to max density). Optionally, some Huscarls can stay closer to the wall and attract any remaining projectiles. During that, join your troops and shoot at the enemy. You can stand around the foot of the wall for best accuracy, as well as picking up missed projectiles of your troops and shoot again.
- After all of your projectiles run out, tell all of your party to fall back. It looks like you wouldn't have any retreating casualty if your party is far away enough. (press retreat button (tab) or personally reach the border and the retreat option will be visible)
- Save your game and repeat.
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Note:
- You should set battle size to max for better time efficiency.
- In each assault like that I can kill about 50 to 200 enemies, depending on terrain and the use of other tricks. Repeatly do this until the number of enemies after poisoning would be low enough, then poison them and assault one last time.
- It's a bit different if the enemies have bow/crossbow or javelin/throwing spear. Javelin and throwing spear are easy to evade (at the suitable range). For bow and crossbow, a shield can withstand many arrows and bolts before breaking, and each companion can have 4 shields.
- Other tricks:
+ with some castles, you may have your crossbowmen climb a nearby hill for much a much safer position.
+ with some castles, you may personally get past the enemy line and stay in a suitable position inside the castle. Control you troops with map. When your troops shoot, you may shoot at the enemies' back, luring them to turn shields toward you and turning backs toward your troop. About how to sneak inside, it should be either when there are not many enemies left, or using an unfair trick: start battle with low battle size, reach the gate/ladder, increase the battle size, the enemies staying on the wall will make space for the new enemies before the new enemies actually arrive at the wall, giving you a chance to get inside.
Screenshot of the tricks:
