For a crash course in the basic characters:
Lena is a Dawn Caste mercenary/soldier that hates the Imperials with a short temper from the Scavenger Lands.
Tavis is a Twilight Caste who is the Exalted version of an eco-terrorist that abhors cities and everything they stand for.
Danielle is an ex-Imperial courtesan/prostitute for house Cynis, who was smuggled off the Blessed Isle by her Dragon-Blooded lover. She loves the fine things in life.
Yes, we're a happy little party, except when Tavis does dumb things. You wouldn't THINK that a harmless Twilighter could cause so much trouble...
(Actually, Lena and Danielle get along pretty well, now. We may be a while forgiving Tavis, though. *grin*)