Selma is an extraordinarily beautiful and seductive young woman: she has an oval face with fine bone structure, a wealth of brown straight hair, and almond-shaped, deep green eyes with thick dark lashes. She favors dark smoky eyes with thick eyeliners, and her choice in lipsticks are of a dark, sultry red appearance. Selma is very aware of her good looks, using them to her advantage every time she can. Her body's quite slim and athletic, making it easy for her to run and sneak around wherever she wants. Her physical features give her an aura of slyness and fierceness, intimidating others but driving many people in like magnets. She knows well how to use her body language and loves using it to flirt. The only thing that gives her status as a demon away is her skin tone and under eye circles; her skin is sickly pale and her under eye circles bruised and dark.

Selma is usually seen wearing either leggings or dark skinny jeans to show off her fit figure, along with either blue, red, or black tank tops. She almost always wears a red leather jacket over her clothes, either cropped, full length, buttoned or with zippers. She likes using black high heeled booties, open-toed pumps, or tall, black boots. She also wears a lot of jewelry, like chain bracelets in either silver or gold, and watches.

Selma enjoys manipulating others, especially humans, to get whatever she wants. Along with it, she enjoys flirting and seducing them too, as her own form of sick entertainment. She likes it when things go her way because it makes her feel in control and safe, especially if it is to her benefit. Other than that, Selma likes to drink tea even though as a demon she doesn't need it to survive, she just enjoys the taste and the irony of drinking it. Fashion and jewelry are her passion, often spending her money on those luxuries instead of actually useful stuff. She likes having the upper hand in every situation and being one step ahead of her enemies.

When things don't go her way, or she has no means of controlling a situation, Selma feels unsafe and she doesn't like it. Not one bit. She may seem like a cold-hearted aloof bitch at times but this is a facade she puts up to hide her true cowardly nature. She prefers flight rather than fight, and would put anyone's life at risk if it means saving hers. She hates coffee, people with a bad fashion sense, and commitment. She's also not fond at all of werewolves and Shadowhunters but if mingling with them and treating them as equals means she gets to survive, she'll do anything it takes then. If you disrespect her in any way or underestimate her, you'll face her at her worse. In her human form, the sun doesn't harm her as bad as it would in her true demonic form, but it still weakens her.

Selma doesn't remember when she was born, or if she was born at all, summoned or created by someone. She just remembers existing, and learning to survive on her own. She is calculating, selfish, and has an extremely well-developed sense of self-preservation, almost always at the expense of any human compassion or remorse. In present day, Selma remains very much the same in this respect. Despite her ruthlessness, it is clear that Selma has deep, genuine feelings for those she truly loves and cares for. In fact, she is usually at her most honest about her true feelings when she believes she is unobserved. Selma's extremely heightened sense of self-preservation has helped her develop a knack for creating elaborate plans and deceptions. Even when she takes a risk, which must be well worth it, she proceeds with caution and a means of escape in place.

Throughout her centuries-long life, Selma has always been tough, feisty, independent and smart. If a task needs doing, she'll find a way to accomplish it, usually through a combination of uncompromising will and skilled manipulation of people and circumstances. Her personal motto - "Better you die than I," - does well to encapsulate her instinct for self-preservation as well as the detached cruelty which many demons choose to adopt.

A succubus is a demon in female form or supernatural entity in folklore (traced back to medieval legend) that appears in dreams and takes the form of a woman in order to seduce men, usually through sexual activity. The male counterpart is the incubus. Religious traditions hold that repeated sexual activity with a succubus may result in the deterioration of health or even death. In modern representations, a succubus may or may not appear in dreams and is often depicted as a highly attractive seductress or enchantress; whereas, in the past, succubi were generally depicted as frightening and demonic.

As a succubus, Selma's human physical appearance is that of a beautiful, healthy, young woman. Her true demon appearance is more sinister; physical changes include fangs, claws, pointed tail and wings. Selma usually gains boosted strength, speed, supernatural level of beauty and some magical abilities, especially dealing with illusions and mental manipulation, when she seduces a man in their dreams or when she's able to place her supernatural manipulation over others. Physical changes include fangs, claws, pointed tail and wings.