Red, what I don't quite get here is "out of character."
Are you saying that its out of character for the group to except help? Look at it this way, you land on a strange planet which screws with a fair bit of the stuff you've come to rely on. Further you discover you've stumbled into the middle of a very bloody war and that somewhere along the line you lost twenty years.
Now out of this someone you recognize as being a moderately sane and honourable man says, "Hey, I have an army here, so I reckon I can spare a couple of guys to guide you to exactly where you need to go and make sure you survive all the other locals.
So you reckon the group wouldn't say yes?
Further, to your earlier point about the Agamari not being part of the quest, why not? If everything is predetermined by the Norns then they could have forseen the Agamari on the planet.