Haruka

From time to time, Haruka will look especially happy when she receives a package for her. Although it's not exactly the general standard for "overjoyed," it's already a rare show of excitement when it's her mood in question, and the only thing that can elicit such joy in her has to be related to the present most popular pop singer, Heath David. Sometimes, it's an album of his, and other times, it's his poster... Even BOX's multifunctional media player has played his music umpteen times.
In Haruka's heart, David is the king of music who's capable of resonating with her down to her soul. Aside from The Eternal and Dpdo, Heath David is the only other topic that can interest her in a conversation, and yet she, a devoted fan of his, has never once attended his concert and insists that she can appreciate his music without having to leave the train.

Haruka was born on a train over a decade ago when Tech was in its early stages of development, making train safety far from what it is at present. It was a time when railway transportation carried enormous risks, and people working in this field were regarded as those who could travel to another world. By chance, two workers met on the train and fell in love, leading to the birth of one of many "train babies." She was named Haruka.
Haruka almost never spent her life outside of the train. Even if she did, she no longer remembers it. Her memory is filled with her life on the trains, including but not limited to eating, sleeping, playing, and learning, so it isn't hard to see why the train is her home, especially since her parents were too busy working on the train to take her back to the city. It was the place where she spent her childhood and eventually grew up.
One night, a huge Chaos Remain damaged the top of the carriage, and Haruka groggily made eye contact with the ferocious, mouth-agaped Chaos Remain. Her screams pierced the silence of the night and fortunately awoke the adults, who made it in time to fight off the Chaos Remain without any casualty... other than Haruka's fragile heart.
From that moment on, she made up her mind on two things: 1. She would never step foot out of the train again. 2. She would never look up at the ceiling again. Her determination has led to her now being able to change the carriage's linear light bulb without having to look up, her actions so polished as though she's just changing a table lamp bulb in her own home.

Haruka, as the train's technician, is indisputably well-versed in what she does. Many train crew members with knowledge of machinery have rated the standard of her repairs with flying colors, and some have even attempted to poach her. Something like "with your capability, you'll surely make a greater difference in advanced repair departments" will sound extremely tempting to any technician, but Haruka has never shown an interest.
"I'm not keen on 'making a greater difference'... My life is only meaningful if I continue living on and moving with a running train," she refused while narrowing her constantly sleep-deprived-looking eyes.
Truth be told, her excuse is flawed. If all she wants is the closed and safe environment of a train, anyone will be willing to pay the simple price of building her own carriage if it means getting someone as talented as her. Still, she turned them down.
A few years ago, the train Haruka was born on retired from service, and her parents decided to permanently settle down somewhere, thinking it was the best opportunity to take their daughter off the train. To their shock, Haruka, who had just acquired her train technician certification, refused to leave no matter what, which led to her boarding the newly operational The Eternal.
The day she stepped foot on it and faced the vacant carriages, she knew this would be where her new life began.