As a grim, serious show with many of the characters having dark and troubled pasts and dramatic twists, it's expected to have quite a few heartbreaking scenes.
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- The flashback to Yo-han's childhood shows the other children shooting at him with a toy gun and laughing when he flinches. They also called him a monster and a devil and refused to talk to him.
- Yo-han nearly gets beaten by his father before Isaac interrupts — and the marks on his back show he's already been beaten.
- Ga-on learns Professor Min is working with Sun-ah and has been using him to bring down Yo-han. He doesn't take this well.
- Elijah's parents died when she was a kid because of her purely by mistake; she knocked over a candle which caused the fire that killed her parents. She didn't learn of this until she became 16 years old.
- When Ga-on finds out the man who conned his dead parents out of their money escaped prison, he screams his heart out in frustration, anger, and helplessness.
- Sun-ah remembering a rare instance of Yo-han being nice to her when she was a child as she's dying with her voiceover saying "you know what? I really liked you, Master Yo-han." As much as her obsession with him is creepy, the ever-cold-hearted Sun-ah probably just wanted to get acknowledged by him.
- Soo-hyun gets shot in front of Ga-on and dies in his arms after she tells him she loves him. Later at her funeral, Ga-on recalls all his memories with Soo-hyun while crying so hard and Elijah weeps with him. Oh, and by the way she dies not long after she and Ga-on become an item.
- Sun-ah shows Ga-on the CCTV footage Yo-han tried desperately to destroy. Ga-on watches it and discovers Elijah accidentally started the church fire that killed her parents. For years Elijah thought Yo-han was responsible for it, and he let her keep believing that to protect her. What makes this more heart-wrenching is Yo-han begging Sun-ah to stop playing the video while this revelation simultaneously makes Ga-on decide he wants to take his own life.