Backstory
Some gods are made when people wish for them, while some are born human and eventually they are revered as Gods through their abilities, such as Marzanna. During an ancient time, she was born a human but, through the apparent abilties she had, she was ultimately recognized and strengthened as a Goddess.
A long time ago, there weren't other gods involved in the land she lived in, so she had all the faith around her. Coincidences were seen around her such as sensing where precious stones where, or knowing if pests were around crops. She was known as a girl who couldn't speak, who suddenly sprouted horns on her head, and who could create miracles. She provided protection to generations of her people in exchange for their support, and all was prosperous for a while. When things eventually began to go badly, there were other deities causing trouble for humans, bad omens who'd bring humans to despair and destroy the land. Due to this, faith waned and Marzanna was seen as a useless Goddess who couldn't save them from tragedy, or that she was the one turning against them. Hurt by the circumstances, she left her townspeople and decided to hibernate as all was beyond her control. During her hibernation, a great forest of aspen trees sprouted, and she stayed dormant in a cave surrounded by a crystalized wall.
Hundreds of years later, Marzanna awoke from her rest, with larger horns and a pale blue hue to her skin. While there were different Gods governing the afterlife, the God in charge of heaven was an especially cruel one that'd taken over the land, sending angels out to hunt demons. Unknowing as she stepped into the new atmosphere, Marzanna realized she would need to hide herself longer.
Occasionally disguising herself as an elderly lady, Marzanna would look around the new Reuya that had been built. People were kind, and despite demons using the town as a sanctuary, Marzanna saw the humanity in their lifestyles and left them as such. Most of the time she would really just wander around the woods, in case she would need to silently guide any lost beings, preferring not to interact heavily with any particular humans. Still, she'd always been a curious person, and when angels were stationed to the town, she became extra careful to disguise herself and ultimately protect the demons that made up a majority of the population there. After all, a god is kept alive through their importance to humans. If she continued to do her good deeds, she would stay for many more years to come
Although many demons are painted in a bad light, and demons themselves paint angels in a bad light, Marzanna noticed that those in the town were very peaceful regardless. She knew the angels were guardians before they were anything like an exterminator, and that their reason for being around was due to a killer that was on the loose. Wary, everyone kept an eye out for the unusual.
Marzanna hadn't seen things like murder in a very long time, always having been surrounded by earnest humans for the most part, finding things such as selfishness or lies incomparable to taking another life. Idling in the form of an old lady, she'd run across Audette Shcheglov who'd taken an interest in her. Perhaps she reminded Marzanna of her younger self, or she just enjoyed the company of another person close to her for a while. Audette didn't pry into her life, but she was chatty enough that Marzanna learned the intimate details of the lives others now held. It could be a bias towards her, but Marzanna has especially decided to watch over the child during these uncertain times, while a child killer is around.