Hmm... never really looked at it that way. I'm used to trying to 'preserve' the life of my mercenary and my initial reaction when it is dying is to let it 'guard'... I'm still getting the hang of 'moving' it the game as well. But, what you does make…
I rarely use the guard button, only when my mercenary is really low on health and there's no turn for my shaman. Yeah, it is pretty cool that it enables our mercenary to block an enemy's attack.
Oh, me likey! Maybe I should really start exploring the world so that I could find and do the quest at the Caribbean! I'm getting a bit bored with my own mercenaries at the moment and the sailor really piqued my interest!