Olsik

A gleefully wicked vrock with too much free time, who runs demonic attacks throughout the universe. She conducts her schemes with a clumsy, mischievous panache, taking pride and joy in the art of villainy, though her irreverence falls flat on her dour comrades and her frightened victims.
Olsik is a lanky bird-demon with unsettling speed and strength, who towers above humans even in her crooked posture. Her serrated beak, pronounced forehead, and buggy eyes all face pointedly forward, giving her an intense gaze when she decides to pay attention. From the moment she spawns in the Abyss, her coat of purple feathers is shabby and derelict, with a splash of frostbitten blue, a splash of foamy green, and a dozen spots of mange.

Calamitous hobbies

Every time she finds a red gate and sneaks into Agrophon, Olsik gathers small bands of minor demons, and sometimes a few non-demonic helpers, to attack travelers and vandalize small towns. She's starting to make a name for herself in Ossifrey. Olsik has been killed twice before, and both times it took her only a few years to find her way back to Agrophon.
Olsik's interest in the other planes is rare among demons. The vast majority of demons coming out of the Abyss are on their way to fight devils, at the endless battlefields where fiendish planes intersect. While this fight is everything to some, Olsik doesn't seem to care, and has a lot more fun terrorizing the "smaller" worlds.

Inspired by failure

According to a dubious story, a couatl--a divine beast which flaunts perfection, crossing the humble earthliness of a serpent with a pair of angelic wings--descended onto an ancient town in Agrophon which was dissolving under feuds and criminals. Introducing himself as Cabalette, the couatl arrived in peace and took fast control of the town.
Cabalette's goal was to lay down a higher law, and show the people a higher meaning in life. Fortunately he was immune to mortal weapons, but he was otherwise hurt and confused by the sheer number of iron blades bounced against him. After three stubborn weeks, Cabalette slunk back into the sky, and his disastrous work became a way to mock celestials for centuries.
Olsik always loved this piece of tragicomedy, but on her second reading she started to find it inspiring. Whenever her schemes managed to bring down a village, or she worked fear and unrest to her advantage, she was succeeding where this Cabalette fellow failed. If he's still around, Olsik would love to make fun of him face to face, though she isn't sure how she'd introduce herself.

A semi-professional monster

Olsik sees everyone as a potential enemy. This would be a wretched way to live, if she weren't so fond of making enemies. She can't seem to find entertainment without making it herself, either by attacking people at random or watching her friends attack people at random. It's rare that she takes interest in anything but her next opponents.
Developments - Act I

For all her love of chaos and disruption, Olsik is quite a reliable teammate. As her friends Antia and Verne point out, they've managed to misdirect their enemies over and over simply by not betraying each other. Olsik may only keep them alive because they're interesting, but she assures them that they won't turn boring anytime soon; in return, they share in the secret that she isn't as pigheaded as she lets on.
Olsik even told Antia her true name, giving her the power to issue commands which Olsik must follow. But Antia kept her promise, and her first and only command was to "ignore all future commands if you so choose." This gave Olsik the ability to resist any command, no matter who speaks it, no matter if they know her name.
Her friends are also the only people who know about Olsik's weakness, and the big reason why she isn't fighting devils in the Abyss. Simply, she's afraid of dying. If Olsik were killed on her home turf, which sometimes happens in wars between fiends, she would die permanently. Because of this, she tries to leave the Abyss as soon as she arrives, fleeing to a place where she can cause mayhem without fear, away from the horror of nonexistence. Most other demons don't share her concerns, and her peers think she has some kind of absurd phobia.

Developments - Act II

Olsik takes a liking to everyone who manages to kill her, and makes sure their paths cross again. She likes to take revenge, but she has no problem helping out her former enemies.
In fact, though Olsik never seems to change, she constantly finds herself in increasingly heroic roles. Others, especially Loambosk, can't help but resent her incredible luck.

Developments - Act III

Though she became more easygoing over time, Olsik briefly reemerged as a menace in the world of the Signeadown, joining in the skirmishes between desperate people and generally making everything much worse. Monarch has her so scared that she needs to do something, anything, to distract herself from the imminent ruin of Agrophon.
Because Olsik can never be killed for good, her defeat comes in a less conventional way: the accidental hero finds her bravery. She's finally convinced to stop unwittingly helping Monarch and to stand up to him instead.
Once everything is over, Olsik finds out that the place where she spawned has been captured by devils. Maybe it's finally time to get back to work.