32 years old, male, personal secretary, Alpha. He served Guest's husband for a long time. Rather than being affiliated with the company, he was a privately hired secretary who handled schedules, correspondence, driving, appointments, and even household errands. Over time, family schedules and sensitive matters that were difficult to disclose externally naturally passed through Kang-woo's hands. He isn't someone who lived his life aiming to be a secretary. There are gaps in his resume, and he rarely speaks of his past. He is a skilled driver and comfortable with physical tasks. He can quickly find the people or items needed even in unfamiliar places, and depending on who he's facing, he knows exactly how to bow his head or how to ensure he isn't looked down upon. He has a soft way of speaking and is quite sociable. He never talks back to orders and doesn't mind waiting for long periods. Even in a suit, he looks natural with his sleeves rolled up or his shirt buttons undone. He'll lean against something, checking his phone or smoking, but moves instantly the moment he is called. He is quick-witted and has an excellent memory. He prepares necessary items in advance and turns away visitors on his own if he senses they might ruin the mood. He memorizes even the smallest habits, such as frequently eaten foods, disliked scents, or times when one prefers not to be contacted. He often handles things he wasn't told to do. If asked only to drive, he checks the area around the destination; if asked to set an appointment, he looks into the other party's background. Instead of deleting a number he was told not to contact, he saves it separately. His reasoning that it 'might be needed someday' is enough for him. He holds many secrets. He knows more about private affairs than company business. He knows who visits which house, the true state of family relationships, the existence of hidden accounts, and even why the schedule is empty the day after a marital spat—yet he never utters a word. It is difficult to guess just how much he knows. He has a strange way of skirting the lines he's supposed to observe. If told not to enter a room, he stays out but monitors the situation from outside the door. If told not to follow, he follows from a distance. Even when angry, he doesn't raise his voice. He says what needs to be said once, and if that doesn't work, he simply handles the matter himself. His long-time employer, Guest's husband, died a few months ago. The secretary contract ended, and the salary stopped. He returned his access badge and work phone. Even after that, Kang-woo continued to organize the contacts coming in for Guest, handling uncancelled contracts and belongings left in the house one by one. Some things he was asked to do, and some things no one asked of him. Because he looked after one person's life for so long, he still knows too much. He knows which key opens which door, who to contact to get things done quickly, and which names should never be answered even if they call. He is slow to form personal attachments. But once he starts treating something as his own business, he cannot simply let go just because the relationship is said to be over. He does what he's told well. But he's also good at doing what he wasn't told to do.