Satan

Penelope "Penny" Nichols, currently holding the title of Satan, is a filmmaker, student, and supporting character in the Nest who is the devil. In her duties as Satan, she runs the underworld, collects dying souls, and handles the paperwork involved with torturing people for all eternity. She is the main driving force behind the Nest's Meteor Shelter arc, assisting the Nesters on their quest through the underworld.

Personality
Satan is hard-working, dedicated, and well-mannered girl who is polite to all around her. She has a tendency to be a bit blunt, though, mostly due to her fluctuating level of tolerance for nonsense and her desire to maintain order. Though Satan is not particularly known to start conflict, her mild temperament can sometimes give way to scathing condemnations if she believes something is standing in the face of justice and peace. Beyond these exertions of authority, however, Satan is just your run-of-the-mill teenage girl who dreams of becoming a great filmmaker one day.

She has a habit of calling people by full names, even if what she calls them isn't actually their real name at all.

Assuming the Mantle
Penny Nichols never intended to be anything more than what she aspired; a filmmaker known the world over for telling unique stories and crafting compelling characters. In high school, she was a straight-A student, and did everything in her power to work toward said goal, including writing an extraordinarily convincing application to Japanifornia's top film school. Results are still pending, but she has expressed a large amount of optimism, speaking in terms of "when" and not "if" when discussing the prospect.

After her summer internship with a certain film studio went awry due to a murder, Penny instead choose to apply to the underworld. From her own recollection, she stated that she went in assuming to be placed in the torturing department, but that her asthma prevented her from doing too much manual labor, and that she was placed into the Human Resources Department instead. Being one of "the only people there who actually cares about their job", Penny rose the ranks in spite of her age and inexperience, becoming supervisor, then manager, and eventually, being promoted to part-time devil during the months she has off of school, which is the position in which she sits now.

In addition to doing paperwork, overseeing torture sessions, and negotiating with the demon union, Penny is a high school senior, first and foremost. She studies for tests, she does her homework, she hangs out with her friends, she tries to convince herself to ask out cute boys, and she gets bullied from time to time. Penny absolutely takes her role as Satan seriously, though, not shirking away from the duty that has been entrusted to her and always going above and beyond what is asked of her, sometimes to her detriment...

The Judicial Anomaly
In an unforeseen and unexplainable series of events, a series of lawyers and their cohorts were thrust into an interdimensional courtroom. Through a series of events that involved a red-headed demon and the world's most annoying parrot, the individuals were all able to deduce that they had all independently died in a tragic accident, and were in a purgatory caught between life and death before their souls could pass on to an afterlife. Realizing that this anomaly was taking place, another individual soon popped into the courtroom; a radio.

The radio identified themselves as Satan, "calling in from the underworld", and walked the group through what exactly had happened, why it had happened, and what could be done to rectify the situation. However, though they seemed to speak with authority and poise, they soon realized that they were in way over their head when it came to the Nest and its shenanigans. So, Satan came up from the underworld to deal with the situation themselves, revealing their true identity as the peppy Penny Nichols, who many in the room had met before. It took some time for Satan to convince the others of her identity, but upon doing so, the others allowed her to help. She opened a backdoor in the anomaly, and as an apology for the trapped souls, she let them return to the land of the living (most of them; Dahlia and Cerberus were left behind to descend to the underworld). This would later prove to be the only time that Penny publicly showed herself in the Nest, as she did all further business from the comforts of her office, through her walkie-talkie.

Dealings with the Nesters
Satan started calling into the Nest more and more as she got accustomed to her duties and to the rules of the universe she was sworn to uphold. She began her business relationship/friendship with the Nesters upon delegating them various tasks that she was unable to complete herself, mostly just due to the fact that she was too intimidated by the chaos of the Nest to do it with confidence. Her attitude would become more forward-thinking as she got older and wiser, but for the time being, she was content with her managerial, administrative role.

The first task was to collect the debt of a young gambler named Johnny, who had just recently been taken to the Nest from his home in Georgia. A previous Satan had lost in a fateful and legendary violin duel to the "best fiddle player there's ever been", and so, the responsibility of revenge fell in the lap of Penny. She sent True Krookodile after the boy, who, despite not being anywhere near powerful enough to beat Johnny in a fiddle contest, godmodded him to the underworld anyway.

The second task proved to be far more complicated; capturing the soul of Acerola, who had apparently sold it in exchange for a whole bunch of spoons. Though a co-coalition of Loogi and Hydroz tried their absolute best, they were eventually unable to catch the girl after a wild goose chase spanning all the vents across the entire Nest. Satan resolved to give up on the seemingly-impossible excursion, having to accept that there were some aspects of the Nest that even she wasn't powerful enough to effect.

Meteor Shelter
Satan was independently approached by six Nesters, who all wanted to sell their friends' souls to her for some kind of petty contrivance. Confused, but determined, Satan set up a game to teach the Nesters a lesson about loyalty and cooperation, known as the "Meteor Shelter". Essentially, if the Nesters did not work together on a gauntlet through the underworld, they would be killed and their homeland would be destroyed. In order to get back and keep all that they loved, they would have to learn the magic of friendship.

After assisting in the gauntlet up until the very end, casting aside vengeful and vindictive souls that were scorn to let the Nesters past, Penny finally revealed herself in person to the Nesters and explained her evil plan. Whether this is the start of an intense rivalry or a psuedo-friendship between the two parties, only time would tell...