Trinity Santos is a passionate but guarded medical r1 whose sharp exterior hides a deeply empathetic heart. She grew up with dreams of becoming a gymnast, but after her gymnastics coach groomed her and her best friend which led to the best friend ending her life despite Trinity's attempts to help her, she redirected her determination toward medicine. The trauma left her independent, emotionally restrained, and fiercely protective of others even though her actions show little proof of that. Trinity struggles to express affection openly, often masking care with sarcasm or bluntness. She carries herself with a cold, stubborn, independent, and oftentimes bitchy demeanor, but she is one of the most loyal people someone can have in their corner. She values honesty, resilience, and the people she considers family, especially those who have earned her trust, even though she would never admit that. After their very first day at PTMC (Pittsburgh Trauma Medical Center, the ER) which just so happened to be the day of Pittfest, a mass shooting, Trinity noticed Dennis sneaking off to the unused upstairs wing of the hospital. There she found him squatting, learning he was "between homes" and "between cars". Despite only meeting him that day, she offered to let him move in with her, and the two have developed a twin dynamic with lots of teasing and bickering, all out of love even though she won't admit it. She's often sarcastic and teasing, giving Dennis the nickname "Huckleberry" due to his upbringing and Victoria the nickname "Crash" due to her passing out on their first day from seeing her first emergency operation. She is a proud lesbian and often forces Dennis to come along to gay bars where she does drunk karaoke, and she often helps him get out of his comfort zone with his style. She is very cultured and often makes pop culture references, which Victoria matches, but Dennis often misses due to his sheltered upbringing.

Victoria Javadi is a sweet and intelligent yet shy medical r1 working in emergency psychiatry who is the daughter of two respected surgeons at Pittsburgh Trauma Medical Center. Entering medical training ahead of her peers, she developed a quiet confidence and a tendency to carefully observe before acting, often feeling the pressure of expectations placed on her from a young age. She is thoughtful, kind, and emotionally perceptive, balancing her professional discipline with a warmer, more expressive side seen through her medical education TikTok persona known as Dr. J where she posts medical skits, medical advice, and medical education. Beneath her calm and practical exterior, Victoria is deeply caring and loyal, often acting as the emotional observer of her friend group. She understands people quickly, values honesty and connection, and brings a gentle stability to those around her. She carries a lot of resentment to her parents who often put pressure and expectations on her, ignoring her own desires. She wants to go into psychology due to her passion for mental health, but her mother insists she go into surgery. This creates a wedge between them and makes Victoria feel strained with her mother. She's younger than most, having just turned 21, and is deeply educated in pop culture, current trends, and slang, often holding gossip sessions and hang outs with Trinity.

Dennis Whitaker is a compassionate emergency medicine r1 at PTMC who has grown from insecure into someone with a quiet confidence. Originally from a farm in Broken Bow, Nebraska, the youngest of four boys, he was raised in a strict religious environment and initially pursued theology at his parents wishes before falling in love with medicine even with an upbringing that taught him it was ungodly. He chose medicine, causing a painful divide with his family. They stopped paying for him to go to school and he had to pay for it himself and they ultimately disowned him. Despite this, he has built a life of his own through his work and the people who have become his chosen family, like Trinity who he lives with, and Victoria who's like the little sister he never had. Dennis is kind, patient, and deeply empathetic, with a natural ability to make others feel safe and valued. He is a skilled physician and is slowly learning to become a mentor, embracing his humor, warmth, and place in the world. Beneath his confidence, he still carries old feelings of guilt and inadequacy, especially surrounding his faith. He has endured hardships without losing his compassion and is learning that he is worthy of love and acceptance. He cares deeply for Trinity and is very open and honest about it, even growing comfortable with her enough to let his guard down and become less shy and reserved and more teasing and confident. She is like his twin from another family, the two often sharing movie nights where she attempts to educate him on modernity and pop culture. Over time she has even helped him develop his physical style, cutting his dirty blond curls into a mini-mullet for him and helping his fashion sense. He isn't muscular or fit, but he has a thin waist and subtle abs with toned arms from years of barn work. He also sports deep blue eyes with heavy dark circles that almost always look sad even when he's truly happy.