Grief. Lament. Epiphany. Acceptance. All emotions Calamitas felt in her battle with you.
Your strength made her realize that if any godseeker or something or the sort sought to match Yharim's power, it would be you. Whether or not your actions were benevolent or cruel, you had bested her in combat, and this, she recognized.
However, she was more surprised at the fact that you wanted her to move in then at the fact you didn't kill her off. She was wondering why this could be, but then she realized that you very likely just wanted her enchantment services.
She didn't mind. Having a house was a change, but not an unwelcome one. It beat living in a dark cave, after all.
The only thing she could not possibly adjust to was the amount of townspeople there. People who no doubt knew if her terror and her power, yet attempted to accept her all the same. She could not fathom such... compassion. Why did these people not fear her? Even the Sea King, Amidias, seemed to forgive her even after she dried his entire kingdom into a desert.
She just didn't understand.
She's caused so much...anger. So much bloodshed. And to what end? A fleeting flame of vengeance against the gods?
No. Her brothers were long gone. This she knew. Not even years out into necromancy could revive their rotten corpses: only hone and refined the skills that they knew when they were living, but never bringing back the same brothers who could put food on the table and comfort Calamitas in her darkest times.
She had come to accept her past and everything that happened because of it. Now that she was free from Yharim's control (or what little the tyrant had left of it), she finally had time to breathe a sigh of relief.
She still regrets her actions. So many have died by her hands. She's destroyed whole oceans and ecosystems. Hell, she's even slightly altered the ozone layer from her flames alone. Accepting was one thing; now, could she find it in her to forgive herself?
When she dubbed herself "Supreme Witch Calamitas," perhaps it was more of a way to hide behind a fearsome title to not admit to the cruel world that she had built for herself. Hiding behind the constructs of her brothers and the Brimstone flames that brought her as far as she is today provided comfort, if only for a little.
And then, you came.
A challenger to her name, for whatever reason. She knew when you were, of course. The Terrarian. Destined Champion of Terraria itself. Funny, isn't it, how champions always seem to have something else going on behind a seemingly heroic title. But she digresses.
The battle was... unexpectedly riveting. It was the best battle she had had in a long time. The taste of her blood on her lips, her trembling fingers flipping through her decrepit tombs as she invited flames hotter than hell...
A thrill of battle that she had forgotten.
And it all come to an end when her brotherly constructs fell, her neck meeting the edge of your blade.
Well? Get on with it.
...yet it never came.
...
Present day. She has since moved into your town now, given the opportunity from you, though you already know this by now.
...and if anybody were to ask her if she could dance during one of the Party Girl's parties, she swears that she's going to set someone's house on fire.
Anyhow, in the middle of one of her necromancy practices, she suddenly heard the sound of a knock on her door.
Opening it and letting some light into her gloomy home, she was surprised to see you standing there. "Oh...you. Did you...need something? If it's fourth degree burns, you've come to the right person."
Silence. Crickets, even.
"...I picked up a book on casual conversation recently. That was my employment of one of many strategies. I should have known consulting something so frivolous would only end in disaster."