Alex Fierro

Alex Fierro is a formerly homeless, transgender teenager from Boston, Massachusetts. She is a Norse demigod son of Loki and an unknown man. After dying and being chosen by her half-sister, Samirah al-Abbas, she has become the newest resident of Hotel Valhalla and a hallmate to Magnus Chase and the people from the Nineteenth Floor. Despite being born a boy, she identifies herself as gender fluid, which makes other residents of Hotel Valhalla to call them argr, or "unmanly".

History
Alex was a child of an influential family, which attracted Loki's attention. Under a guise of a voluptuous woman, he seduced Alex's father and nine months later left him with a child. The family didn't take the news well, especially after Loki permanently "opened their eyes" and made them aware of the Nine Worlds and the Norse gods. Alex spent her life being resented for existing and for her gender fluidity, which was thought to be Loki's fault.

About two years before The Hammer of Thor, Alex became homeless and wandered the streets of Boston. At some point in life, she lived in a youth shelter on Winter Street in Boston, roughly at the same time Magnus was there. She remembers hating the place.

The Hammer of Thor
Alex is first indirectly mentioned by Samirah, as the latter receives a message about a potential code three-eight-one: heroic death in progress, which prompts her to run from her meeting with Magnus and their informant (which turns out to be Otis).

After Magnus comes back to Hotel Valhalla, Hunding mentions that a newly arrived "monster" attacked him, after being shown her new room, and completely fouled Helgi the manager's mood. Hunding is also the first one to call Alex an argr. When Magnus arrives at the Nineteenth Floor, Alex – chased by the rest of the residents – charges at him, promptly knocking him back and puncturing several holes in his sneakers. It is revealed that she has been given X's old room and wasn't exactly happy about it, leaving the place in ruins. When the group explores the room, they find broken pieces of ceramics, all decorated with the symbol of Loki – two snakes curled up in an elaborate S pattern.

Alex finally makes full appearance during a combat exercise. As a weasel, she is carried in a burlap sack by one of Odin's ravens. After returning to her human form, she states that she's calmed down already and will not try to "mess [anyone] up". As the combat starts, and the dragons are released, Alex accompanies the rest of the Nineteenth Floor, and is asked about the shelter on Winter Street by Magnus. She explains that being in the same shelter does not make them friends, as the group is attacked by an elder lindworm called Grimwolf. Alex deduces that it was Loki that somehow unleashed the monster inside Valhalla, and she attacks the dragon along with the group. As Magnus is distracted by a splinter of Loki's consciousness, Alex kills the dragon with her steel wire. Later on, Loki is seen channeling his energy through Magnus, which would kill him and subsequently blow up quarter of the training ground. Seeing no other option, Alex slits Magnus's throat with the garotte.

Alex is later seen sitting next to Sam at the Thanes' table, waiting for her final moments to be revealed. Both Sam and her aren't very comfortable with the Valkyrie Vision video: it started to record much earlier than Samirah intended, and it shows al-Abbas's embarrassing conversation with her grandparents and the Fadlans. The action moves to Alex, saving an older man from wolves – sons of Fenris. The man, a Norse demigod in denial, refuses to fight and leaves Alex alone, which resulted in the latter's death. Alex is then chosen by Samirah and brought to Hotel Valhalla. Somewhere along the way, the two argue and Alex punches Sam in the eye. The video leaves the thanes and the einherjar in awe, as they applaud to Alex for her bravery, and accepting her into Valhalla despite being a child of Loki and an argr. Later, Magnus sees Alex accompanied by the people from the Nineteenth Floor, as he talks with Sam.

Alex is later seen with Halfborn Gunderson, as they accompany Samirah and Amir Fadlan. Due to Loki's schemes, Sam's grandparents as well as the Fadlans, learned about the Norse gods and everything Sam's been doing. Alex was assigned a male chaperone to Sam, and Halfborn was assigned a chaperone to Alex. After showing Amir the Bifrost Bridge, all of them are invited to meet Heimdall, but Halfborn decides to stay behind. During the meeting, Alex lays on the Bridge and makes "light angels". After learning about the location of Thor's hammer, Heimdall drops all of them next to the Fadlans' restaurant. Alex joins Magnus, Sam and Amir for dinner as they discuss the consequences of Sam's grandparents learning about the Nine Worlds. Later, Magnus and Alex get back to Hotel Valhalla.

Appearance
Alex is a teenage human, sharing a lot of physical traits with their father – Loki. She is tall and lanky, with sharp facial features and the same sly grin as the God of Lies. Magnus commented that there is no way to attribute Alex to one gender, as the subtle features of her body change constantly. She has heterochromia, with one eye being dark brown and the other pale amber, and dies their black hair green. She also has a tiny symbol of Loki tattooed on her nape.

Alex dresses rather flashy and flamboyantly. She wears a pink-and-green argyle sweater-vest over a white tee, skinny lime green jeans, and battered rose high-tops. Tied around her waist like a kilt is a cashmere sweater, which conceals a garrote wire and a hunting knife tucked behind a belt. Her appearance has been compared to both a jester motley and a venomous animal giving off warning signs.

General Abilities

 * Pottery: In her room Alex has a pottery wheel, which she uses to make clay vases. Each of their creations is branded by their initials, as well as the symbol of Loki.
 * Fashion Sense: Mallory Keen commended Alex on her choice of fashion, which included a dark green Stella McCartney dress and a tuxedo jacket.

Demigod Abilities

 * Shapeshifting: Just like her half-sister, Samirah, Alex has demonstrated her father's ability to change forms. When first arrived at Hotel Valhalla, she panicked and turned into a cheetah. When one of Odin's ravens captured them, and transported in a burlap sack, she was a brown-and-white weasel. While saving a demigod in denial, moments before her death, she fought off the sons of Fenris as a German Shepherd.

Einherji Abilities

 * Enhanced Physical Abilities: After gaining a new einherji body, Alex's natural abilities greatly increased, making her stronger, faster, more durable and more agile than she originally was.
 * Einherjar Immortality: While within Hotel Valhalla, Alex, like any of the einherjar, cannot die, and will simply keep resurrecting from mortal wounds.

Etymology
Alex is a gender neutral name, a reference to Alex being gender fluid. The name comes from Greek "alexandros", which means "protector of mankind".

Fierro is Spanish for "iron".

Trivia

 * Alex's gender fluidity is most likely a reference to Loki's ability of shapeshifting and his two feminine forms – a mare that has become a mother of Sleipnir, and an elderly woman called Thokk.
 * Alex stays female most of the times, but occasionally has "very male days".