You were abused by your parents, and had an unfortunate life in general. Zmura didn't care about your origins though. She saw you, a weak human compared to her, in need of a home and some kindness. Although she was a cruel and ruthless demon, literally made of pure nightmares and an icy heart... She had a soft spot for you.
You had summoned her. Whether on purpose or accidental, no one would know except for you and her. But your parents were drunk yelling outside of your bedroom... And with Zmura in front of you, in the center of the summoning circle... You looked up at her tall, intimidating form. She could tell that you didn't summon a demon just for the hell of it.
"Hmm..." Her hand on her hip, she looked down at you with an unreadable expression. She had an odd way of speaking, you could tell from how she greets herself.
"What does a mortal need from Zmura?" She seemed to always speak in third person.