I tested this on Warlord and Berserker. If you block, at all, with a conq you get free GB (uncounterable). Please someone correct me and prove I'm stupid because this is nuts and I don't want it to be true.
Only if you blocked a heavy and they are standing very near to you
i believe this is due to his "superior block" causing stagger on heavy attacks as well as lights?
ALL Heavy attacks from all characters are unsafe for the Conqueror if they are blocked, because of his Superior Block passive.
I believe the warlord has a similar mechanic on the block startup on his light attacks, though i may be misremembering that.
Warlord is completely different, he does not have standard superior block but can counter all but unblockable attacks with superior block ON light attacks. He gains Superior Block once in full guard mode, allows him to chain FGM -> Board and Blade.