Cassandra Bittermoon is the daughter of Horfor (an elf) and Clarissa Bittermoon. Unlike nearly every other adventurer out there her parents are still alive and they get along with her quite well. They are running a tinkershop in Luskan. Horfor Bittermoon always wanted to have a son though so he could take over his shop one day. He hasn't high expectations that Cassandra will someday.
So Cassandra left Luskan to proove herself and to show her family that she can take responsibility and risks and is able to manage her life.
Stranded in several citys the only people helping her out were the rogues living on the streets as well. Even though she doesn't necessarily like the life of a thief it still gets her enough gold to survive.
People who have treated her quite qell in her recent past are Reavus (a thiefguildmaster), Jack of Shadows and Rapid Chicken (two insame but friendly thieves) and her best friend Jill (she is a well known burglar and trap artist).
Cassandra biggest wish would be to live a proper life" in the eyes of her parents. This is to own a house and be well repected, even a little famous.
She has killed before... she sees a need in it and is ruthless. As long as the "puplic" still thinks she's "proper person" she'll do anything which benefits her.
The worst thing she did so far is killing the inncocent merchant's family - the "Bilbaos". They woke up as she tried to rob their house in the night. Frederick Bilbao remembered her face right away and called her name. Cassandra was so shocked that she has been spotted that she killed the merchant, his wife and thier 10 year old boy. She was very shocked about her own actions. She ran out and immediatly called the guards pretending she has been watching a robbery herself.
For now she is looking for other places to get fame and acquire wealth.