Y'know, I was playing this last night, and I thought that for a laugh, I'd have Eirika attack Breguet, because she had the Rapier.
And I distinctly recall that one guy saying that both Rapiers and Armorslayers can take down Heavily-Armored foes.
And as luck would have it, she one-shots him with a crit.
Levels off of it too.
I'd say that I was damn lucky, but maybe she had the advantage due to the rapier?
I wouldn't really know though, as I've not played an FE game before.
But due to experience with games like this, I do fairly well.
Hell, I got my start playing games like these with Final Fantasy Tactics.
The original one for PS1.
Which made for some immensely amusing and infuriating late-game random encounters.
(Y, hello thar LVL99 Red Chocobo.)