My character is an escaped slave, and if it is ok with Venn I was going to say that his character helped Kalal escape the waste. Since Yamanu is a "native" desert dwelling creature, and very sneaky, I figured he could be good at that. I don't know if that jives with his military background, though.
bears' character's draconic nature could be a good reason for Kalal to have taken up with him, since Kalal worships Syberis. Given that his character is young and a bit naive, Kalal would probably think he should try to protect him.
He would also want to protect the old giantess, because he thinks she's a bit daft but good-natured. He also worries that her dabblings with dark forces will one day come back to bite her, and he wants to be there when it does.
So I could certainly see why Saru, Kalal, and Goldflower would be traveling together. The other two seem like they're misplaced soldiers with nothing better to do, so maybe they just took up with us to have traveling companions, or out of a sense of survival (it's easier to get by in the wilds when you have allies to cover your own shortcomings).