The protagonist of the story, a young man whos apprehensive about technological advances and the existence of androids. Hes your stereotypical teenager: rebellious, stubborn and emotional; however, he is highly self-aware and intelligent. Unfortunately, he feels lonely due to having a strained relationship with his parents. He often clashes with his father, and his stepmother rarely comes around.
- Bad Liar: Tries telling Lucy how awful her cooking is in an attempt to tease her, but she sees right through him because he smiles while saying so.
- Brilliant, but Lazy: Said to be the second-best student in his class after Dr. Gears, but puts a minimum amount of effort into his studies and attendance.
- Defrosting Ice King: Possibly, given the right choices.
- Desperately Craves Affection: Part of the reason he latches onto Lucy is due to Parental Neglect.You: Unlike the other kids at my age, I never had a mother taking care of me ever since I was little. My father was always so focused on his work, too. And my new mother is nothing more than a distant stranger to me. She never stops by our place unless she has a good reason to. So basically... I've never had anyone take care of me when I was sick. That's why, the fact that you were here to stay by my side...
- The Determinator: Spends 15 years learning robotics (which he hates) just to figure out how to rebuild Lucy from scratch.
- Featureless Protagonist: The player is meant to be the protagonist (hence the protagonist's name of "You"), so his appearance in CGs follows the trope example of a vaguely dark-haired young man whose bangs hide his face.
- Like Father, Like Son: The protagonist despises his father, but inherited his father's extreme dislike of robots and admits it to Lucy. He eventually warms up to her, though.
- No Name Given: The protagonist is referred to as "Master" by Lucy during the entire game, and the text box lists his name as "You". At one point early in the game, you can enter a name for him, but this does not matter as Lucy will continue to refer to you as Master and even the protagonist will reject the name you give him immediately after. This is because he is Dr. Ryu, the doctor who appears in the interludes throughout the main story.
- You Are What You Hate: Became a robotics engineer despite his hatred of the subject, just so he could revive Lucy.
Lucy, aka PIM-001
Thrown out for scrap, Lucy (model number: PIM-001) is a cheerful, lighthearted android. She is a "premium model" who was abandoned in a junkyard for unknown reasons. Not only does she look and feel human-like, the way she expresses complex emotions feel all too real.
- Ahem: Fond of doing this, usually with a smirk on her face.
- All-Loving Hero: Due to the way she was programmed, Lucy cannot discern between good and bad people. This leads to several unintentionally humorous situations throughout the game.
- In the Epilogue, even though the protagonist's father was a complete Jerkass to her at best and her destroyer at worst, she gives the father hope that his son will visit him again.
- Bare Your Midriff: Her outfit includes a midriff-baring top, exposing the serial number on her stomach. Later PIM-model robots seem to follow the same fashion sense.
- Beauty Is Never Tarnished: Even after Lucy is immolated, the CG shows her body is more or less intact with just burnt clothing, despite the game saying that she is completely destroyed.
- Dull Eyes of Unhappiness: When she is found in the scrap heap and when she "dies", she sports these.
- Lethal Chef: Subverted. One of the first features she points out to the protagonist's father while trying to quantify her worth to him is how excellent she is at domestic duties.
- Gaussian Girl: A variation, as she's frequently depicted in CGs with lots of strong lighting and bloom, making her look almost angelic at times.
- The Pollyanna: Likely as a result of her programming, but she's a relentless optimist.
- Quizzical Tilt: One of her portraits includes this.
- Restraining Bolt: If Lucy harms a human, she is programmed to break down immediately.
- Ridiculously Human Robots: He's repeatedly noted to be far more human-like than any previous robot. She even cries Tears of Joy in the Golden Ending.
- Robot Girl
- Sex Bot: Reveals herself to be "fully functional" as detailed under Moment Killer.
- Stepford Smiler: Reveals herself to be one after your illness - she was smiling in spite of the emotional pain she was receiving earlier, fully aware of how mean you and your father were being.
- Third-Person Person: Always refers to herself as Lucy - until after you unlock the Golden Ending, where she uses "I" after recovering her memories, 15 years after you'd first found her.
- Undying Loyalty: To you. She refuses to refer to you as anything but "Master" the entire game, even when you try and correct her.
- You Gotta Have Violet Hair
Your best friend. As his name suggests, he's an expert in all types of machinery.
- Allegorical Character: As his liberal use of androids and genius with technology suggests, Gears is meant to represent those who accept change as an inevitable part of life, unlike the protagonist and his father who yearn for the good old days sans robots.
- Jerk with a Heart of Gold: Though he can be rough around the edges, he attempts to help you get over the loss of Lucy.
- Everyone Calls Him "Barkeep": His real name is Baek Du-San, but the only time he's referred to as such is when he introduces himself to Lucy.
- Odd Friendship: Gears is a Gadgeteer Genius and obsessed with technology, while you are a hater of everything tech. Yet the protagonist describes him as a "good guy" and is best friends with him.
- Robosexual: Tells you he finds female androids attractive and employs five or six them at his home.
An antique shop owner who works part-time as a mechanical repairman.
- Anime Hair
- Goggles Do Nothing
- Mr. Fixit: However, he can't fix Lucy after she is destroyed in a fire.
- Small Role, Big Impact: He has minimal dialogue and screen time, but he takes you as an apprentice after Lucy is destroyed, laying the groundwork for your eventual future as a robotics engineer and Lucy's revival 15 years after she is destroyed. In fact, he is arguably the most important character in the game aside from Lucy and the protagonist as both choices you need to make in order to get the True Ending involve him.
(Called Ichinose in the Japanese dub.)
- Beard of Sorrow: Grows one after Lucy "dies" and he spends the better part of two decades trying to rebuild her.
- Everyone Calls Him "Barkeep": Of a sorts - he is only called by his real name once or twice throughout the entire game, and is otherwise simply referred to as "Doctor". He is actually you, the protagonist, 15 years after the original ending.