Backstory
When Artemii was born, simultaneously, his mother passed away. Life conditions weren't the best during a time of interspecies wars between angels, demons, and humans. With his human father at his side, he was determined to protect his son and raise him well, but in the end, Artemii was stolen away during an ongoing raid. While his father Radomir became a demon in the aftermath of his despair over losing his son, believing Artemii had passed, he was instead raised by a human couple until his death later on in his childhood.
Artemii's adoptive parents, titles unknown to him, were strict and hardened in personality by the cruel outcome of their world. They'd noticed Artemii crying alone when they found him, but it was just that his birth father was helping a neighbor in need during trouble. His new parents never admitted he was taken, believing his real family to have died, so they raised him like one of their own. With a couple siblings in the next few years, Artemii thought he was the eldest sibling in his family, one who's role was to protect his family, and inevitably to hate demons as much as his parents did. And so that's the life he led up to the age of 11. When his new family had been killed at the hands of human bandits, he learned then not to harbor any ill will towards demons specifically, as a handful of terrible humans existed after all. Unable to protect his family as a child, when he went to heaven, he made a voluntary choice to join the military rather than resting in peace as trouble continued on earth. At least, when his parents knew they wouldn't make it out of their predicament, they admitted that Artemii wasn't their flesh and blood child. Perhaps joining the military was to keep his mind off the fact, because spending his afterlife with a family that technically wasn't his seemed painful to him.
During his time as an angel, Artemii intended to stay by himself and not grow attached to others, closed off after his experiences being misled growing up. He aimed to become an examplary soldier and simply carry out his duties, but regardless, he wouldn't end up doing everything alone. Soon enough, Chryanthos and Charaniel became his dear friends, companions that he wanted to continue growing up with.
Chrysanthos, the most outgoing, was the first to integrate himself in Artemii's afterlife. One way or another, he said Artemii reminded him of someone he'd once met, but Chrysanthos' influence on Artemii was that of an older brother towards a younger brother. It would be good for Artemii who felt others could rely on him, but then who would he rely on or trust? Charaniel had that impact as well, similar as a stoic and serious person, but it was easier for the two to realize their overworking habits by pointing out in the other. She was also dear enough to him like a sister.
When the trio decided to become stationed on earth together, they were assigned to a tranquil town, Reuya. While it was known that way, the town was unnerved by rumors of a dangerous person in the region, namely a certain demon coined Baba Yaga who was taking the lives of children regardless of them being a demon or not. With how peaceful the town was in the beginning, Artemii didn't expect the serial killer to come by at all, but the peace of mind in everyone wavered as sightings became more and more prominent.
Like everyone else, Artemii wanted to protect all of the inhabitants and children of the town, but Audette in particular was one he'd grown fond of. She was a demon by birth, yet a good natured child who extended her kindness to Artemii, earning his concern when he'd found her taking shelter under a tree during a blizzard. Perhaps she reminded him of some siblings, or she was proof to him that content people existed despite their predispositions, but she did mention a few times that she'd met a demon matching the description of the serial killer.
Artemii had thought about it a few times, what he'd do if confronted with such a merciless person. The easy answer is to defeat them, but that's also easier said than done, and there's the chance of him becoming a killer himself. Still, he figured if the chance came he'd want to fight them regardless if it's for the greater good, but what if Baba Yaga was someone he knew? In that case he wouldn't be prepared, as it's a thought that never crossed his mind, and a fact that he doesn't know is true. After all, the serial killer responsible for an ongoing string of deaths, the demon named Radomir is the result of his father's strife over Artemii's separation. While he wouldn't recognize his own father, if he were to meet Artemii, Radomir would know it immediately.