I’ve done some further testing and can now confirm that if you have one of your brothers standing in front of the intended target of a ranged attack and the shot decides to hit the blocker instead of the intended target then the ranged defense of the brother actually being hit IS COMPLETELY IGNORED.
I tested this by using cheat engine to make a brother that has 1,000 melee defense and 1,000 ranged defense and replaying a fight against an army consisting solely of archers/crossbowmen several times. When standing or fighting by himself, the super brother was not hit a single time despite standing there and allowing the enemies to shoot at him endlessly. I did the fight 5 times, went to round 10 each fight and then retreated and reloaded the save, and he wasn’t hit a single time. I then played the fight 5 times over again, 10 rounds each, with a naked brother standing behind him (to draw their fire since they love shooting at low-defense characters), and he was hit 17 times. None of these shots hit the shield, they all hit the actual brother and he died in all but one of the tests (He was wearing special named armor and helmet as well).
Seems pretty conclusive to me. If your brothers are standing next to each other you’re completely at the mercy of the enemy crossbowmen. Just pray that their AI wigs out and they just run around for the entire fight instead of actually shooting. Not a fan of this situation to be honest. Fighting a caravan with 2 crossbowmen is scarier than fighting orc warriors and warlords. At least the orcs can’t kill one of my brothers before I even start my first turn. The only way to stop this is to get my initiative high enough that I move before the crossbowmen, but that’s not really feasible without the rest of the noble army tearing me to pieces.. especially since the noble armies are allowed to be a lot larger than your company. As it stands, fighting the noble armies is ‘easy’ in that I’ll always win the battle, but it’s dangerous in that there’s a chance one of my brothers will just die in one turn. If a brother doesn’t die, I usually take 0 hp damage, just some minor armor scratches, but if the RNG gods find me unworthy, the crossbows will just insta-snipe a brother and I’m out of luck.
Side note: On the topic of shields, you only get the ‘shield hit’ if the attack would’ve hit your brother without the shield’s extra defense bonus, and it does 1 damage to the shield no matter what weapon is used, as far as I can tell.