Like Ukitake, Stahma's projected exterior personality wasn't her true nature. She had a very carefully crafted facade, playing the subservient role a Castithan woman was supposed to be all the while hiding the viper that she really was. She just knew when to unleash the viper and when to be the subservient woman. Manipulation was certainly what she was skilled at.
Still, she was certainly not uncaring. Stahma had a heart and emotions, and she tended to care more than she wished to say. After all, she did care for Kenya deeply, but her love for her husband Datak had been stronger. So when her affair had been discovered by her husband, she'd done what he'd asked of her to make amends. Granted he should've just killed both Stahma and Kenya outright as was the Castithan way, but he had given Stahma a different option. Datak and Stahma shared a love that defied human understanding to the extent Stahma had poisoned her lover when her husband had asked it of her.
Seeing the tired look in Ukitake's eyes was worrying. "It is alright," she responded with a gentle smile. "You look tired. Are you ill again?" She remembered their last conversation a couple days prior about Ukitake having been sick recently. Her lilac eyes took in details. Illness was something she'd seen often in others. Castithans had a remarkable immune system and they did not fall ill so easily when compared to other species. Her head remained cocked, her posture rod straight, fingers laced at her waist. She had a white veil covering part of her head, as she always had when she was outside of her room.