To any stranger who enters Umbra Magna, Nephthys is a dangerous and frightening enemy. She uses her status as Guardian as an excuse to fight and kill, both for fun and to please her sadistic needs. Fighting back against Nephthys fuels her lust for blood even more, especially when her foe is able to inflict non-lethal wounds onto her, as the sharp feelings of pain only seem to arouse and excite her.
Even though she's a ferocious and borderline psychotic monster in battle, to the few people she is friends with she's quite a different person. Outside of combat she's a carefree, adventurous and expressive girl.
The ones she cared most about used to really only be her brother, Adranus and her sister, Mazu. Adranus for their shared love of fighting and careless personalities and Mazu for being someone she can both joke around with and talk to on a serious and personal level. However, there was one other person who would show up in Nephthys's life who she would come to care deeply for. She fell in love with a fleeing girl called Eve, who she spared and took care of. Eve managed to open up a much more sensitive and loving side of Nephthys that nobody had ever really seen before.
Being a girl of rather short stature, Nephthys might not look like much on first glance. On closer inspection she may come across as a bit more imposing however, having sharp eyes and even sharper fangs. The dark bags under her eyes contrast to her very pale skin and her eyes shine dimly in the dark. She usually lets her long, messy hair down, but will sometimes put it up into two pigtails or one long ponytail. Despite not looking very strong, she does have a slightly toned body even if she doesn't work out. Nephthys is well endowed, to say the least, something that is made more noticable by her small size.
When it comes to her outfits, they match her rebellious, carefree personality and gloomy physique very well. The reason for this being that she makes all her clothes herself. When she goes out her usual getup consist of a pair of black shorts and a sleeveless black button-up coat, with pink highlights and raven feathers placed where the right sleeve ends. She wears gloves with baggy sleeves and ripped up fishnets. The boots that she wears are fastened with belts and have high soles. When she's at home her casual outfit simply consists of a short, black top and tight shorts.
- Nephthys and her older sister Mazu are the only two Sanctuary Guardians to get into a serious relationship with someone.
- The designs of Nephthys' outfits are based off of various real world alternative clothing styles, mainly punk and modern gothic.
- Nephthys is the only Sanctuary Guardian to have some form of a transformation. One of her methods of attack is to fully embrace her animalistic side, at which point she goes berserk. Her fingernails and teeth grow to be longer and razor sharp and her eyes look completely wild.
- Nephthys is a sadomasochist, deriving pleasure from inflicting both harm upon others and herself.
- Even outside of her sadomasochism, Nephthys is quite perverse. She constantly tries to seduce Eve, whose subsequent embarrassment excites her even further.
- Conveniently, both Nephthys and her lover Eve do not physically age.
- When Nephthys is riding on one of her sister Mazu's ships, her favourite thing to do is to climb onto the top of the masts and swing down with a rope.
- When Nephthys goes to visit her brother Adranus they always spar together, usually their younger brother Dhara is there to eagerly join them.