Calisto is an AMAZING character and far and above my favorite villain in the series.
I felt like there was a lot to her we don't know. She's the only character so far we don't know the true name of, and I'm willing to bet that slipping between all those roles, perhaps even she has forgotten. I believe one of the few genuine things that is truly hers is her laugh, which she carried from Calisto to Shih-na in the end.
I know many found her to be a conniving bitch with no room for sympathy, but I believe it's more complicated than the game just trying to make us feel sorry for a pretty face at the last moment. Headcanons ahead!
I've always thought that perhaps Calisto had a bad start in life and wanted to escape who she was, through acting as new identities and through laughter, which is in her words, the best medicine. She got involved in the smuggling ring but found herself getting too invested when it came to Byrne and Badd, so when she had to kill Byrne, it was a blessing and a curse: she could cut off the source of emotional ties that would only interfere with her thrilling life, that could possibly bring her down to the core of the person she originally was, who she'd been trying to leave behind, but along that same vein, she couldn't have known how much it could hurt her. I believe she was being honest when she said that killing Byrne was not a pleasant assignment, for any number of reasons.
Onto the Lang/Shih-na dynamic...gosh talk about tragic. I think she really may have fallen in love with him and his determination and no-nonsense attitude and how genuine he was. Seven years is a long time to stay joined at the hip to someone and it's only too clear she knew him inside and out. When the time came for her to be apprehended, Lang was the one to capture her-and protect her. Perhaps it could be chalked up to Lang being much stronger than her and thus able to restrain her with no trouble, but I did find it somewhat unusual that a simple 'crook' like her would be above going for his injured leg to try and escape, had she wanted to, for Lang was wounded.
I also believe she was truthful when she told Lang he was the kindest man she'd ever met: I assume she called him stupid perhaps because of her pride. She doesn't want to or isn't ready to admit to herself or anyone that some true part of her surfaced enough to feel for someone, feel for him. These two are my OTP for the series I can't even-ugh, just wow I love their dynamic. I can only imagine how she could've felt, as the years went by and her feelings for him possibly deepened, but she was already in too deep with the smugglers and couldn't very well back out when she was so close to someone that could be in serious trouble because of her no longer leaking information received from him, hence rendering him worthless/disposable/subject to whatever her former superiors would deem to do with him now that there was no longer a tie from him to her to the ring.
I believe that somewhere along the line, some part of her wanted out. Perhaps she didn't even know what she wanted. Maybe she didn't even know herself. Her instincts were simply to protect herself-she's at a loss as to what to do if she entertains notions of looking out for others, and I believe that being placed with Lang exposed her to exactly those feelings.
Jesus christ I could go on forever about my love for Calisto/Shih-na as a character so I'll stop here on that point and take a moment instead to gush about how well-thought out her name is.
'Calisto' can refer to a genus of butterfly. Her butterfly reference can be a nod to where she first rests her wings for capture-apprehending Kay for Manny Coachen's murder in Babahl, whose country bears a butterfly upon their flag. One calisto species in particular, the calisto smintheus, primarily eats flowers, one of which being the pavonia fruticosa; a flower resembling the one upon the Allebahst flag. And it is by Calisto's dropping of the garden sticks that is the undoing of the antagonist heading up Allebahst's nation.
Less obscurely, 'Yew' is a type of tree that thrives and reproduces by branching out with several different roots in an effort to survive, not unlike how Calisto survives by assuming many identities as she needs. It is also poisonous if the foliage is consumed. Lastly, it can grow in just about any area or condition, a testament to Calisto's adaptability.
Finally before I get way too long winded, I'll mention that phoenetically, 'Calisto Yew' can sound like 'callous to you'.
I just love her so much.
It that weren't apparent ahaha.