Crossbows can penetrate plated armour but the distance must be close and you need to hit the plate in one of the places it's not rounded. Otherwise it will bounce off like any glancing blow. I doubt anything other then Arbalest or siege crossbow is able to penetrate multiple plates(those soldiers were supposed to wear excessive amounts of armour). Crossbows used weren't of arbalest nor siege kind.
@LowSanity The Genovese were trained in crossbow warfare and received the Bonus Penetration skill to bypass even the thickest and most round armor. Wear heavy armor, double your armor, triple your armor, you can't stop them.
What a cliffhanger!
(Also, in the olde English they used the word arbalest, though the imagery sure didn't support that, and the bolts weren't even tipped.)
@Solaz@ninjadork To be fair, even if they didn't die they will either collapse due to exhaustion (they are after all running with full armor they just wear for the first time) or retreat.
It probably won't work like this irl, but I can't really judge because I don't know the effective range of crossbow and how far they are in the manga