Personally, one of the things I love most about CoC II is that Kasyrra is a very nuanced villain. I won't deny that Kas is evil and caused immense suffering to Savarra either through her direct action, her empowering very bad people, or just the introduction of corrupt magic in an already post-apocalyptic world.
Interestingly enough, I always found that Kas motivated by a malformed heroism that is a twisted reflection of her past. In a sense, she is "halping" people, but she is so self-absorbed that she really doesn't care about the consequences of her "halping" outside of how it benefits her. Take Alissa for example. Kas did indeed "halp" Alissa get an heir, but Kas probably never asked herself "should I help this person" or "what will happen to Alissa or the Elves if I help them." Once Kas got what she wanted, it was not of her concern. This pattern is very similar to the Alrune. Kas helped the Alrune, but ceased caring once she achieved her objectives.
Another factor that make Kas interesting is how her power clashes with her obsession. Demons become basically motivated by their obsession. Generally, their motivation is either sex, money, and power, and their demonhood actually helps in pursuing their obsession. Now their obsession will never be satisfied, but they can always work on it. Farrah will never have enough money, but she can always earn more money.
For Kas, her Demonhood makes her obsessed over the one thing that Demonhood robs you. The ability to have children and form a family. Now Kas tries very ways to get around this, her most successful being her adoption of the Dragons, but even then Demonhood cheats Kas.
I don't think Kas is truly capable of loving someone else. I not saying that she doesn't want to. She tries to and can create a facsimile to love. If you pursue a relationship with Kas, she will be fond of you, care about you, and want to be with you, but you will be first and foremost a means to an end.
