Chiana was originally supposed to die at the end, but producer David Kemper enjoyed her performance so much that he rewrote the ending of the episode and eventually made her a main character.
The knife Rygel produces, and which Aeryn takes from him, as he plans to kill Durka is actually a Sgian Dubh or "Black Knife" worn tucked in the top of the hose as part of Scottish Highland kilt attire.