Cornelian Cherry

She is the second in command at El Academy, hailing from the prestigious Cornus family, known for producing exceptional swordsmen who have produced the Guardians of the World Tree multiple times. With her golden-yellow long hair and captivating voluptuousness, she was considered a cliff-top flower due to her distinct emotionless expression and tone. However, after a training camp, she became much closer to other novices, causing the image of the "cliff-top flower" to fade away. She developed an interest in Lee Si-heon, who became stronger than her in an instant, and they became close friends. After getting to know her, it's apparent that she is kind and innocent, almost like a beloved younger sibling or a pet. In fact, Lee Si-heon describes her as a "soft and round-eyed retriever with a more innocent charm than a sunflower." Being around her brings comfort, and he even jokingly calls it "Dogwood Therapy," treating her like a complete mascot. Interestingly, she struggles with remembering people's names and often mispronounces them letter by letter. However, her written scores are top-notch, suggesting that intelligence isn't an issue. Growing up like a greenhouse flower, she seems to absorb all information from her surroundings like a sponge, often unaware of the world around her. Due to her friends' influence, she's developed a hobby of eating and posting online. Currently, she's a fanatic for spicy tteokbokki, a prominent member of the Tree Inside Swordsmanship Gallery, and a goddess who shines brilliantly. With the appearance of an affectionate and playful puppy, Lee Si-heon likens San Su-yu to a rural dog or a golden retriever due to her strongly innocent yet oddly foolish and adorable behavior. In Part 1, she displayed only her pure and fierce traits, but by the time of Part 2, three years after recovering her sense of self, she was described as having matured significantly. She exudes an atmosphere reminiscent of the distinctive aura felt from the old Cornus family members and even from the ancestors, as mentioned by her colleagues. However, whether this atmosphere aligns with a positive direction like intellectual and resolute aspects, or leans toward a negative direction of obsession to the point of madness with a specific subject, remains undisclosed. What's clear is her near-fanatical trust in Lee Si-heon, and she still harbors a fixation as seen when she recalled the events of Part 1 and was greatly moved during the Tree Conquest War. Moreover, unlike other heroines like Lee Se-young, who display logical and intellectual sides, or potential rival heroines whom she can identify at a glance, Si-heon only showcases her fierce side, maintaining a façade of being deeply secretive. Readers suspect that she might be putting on an act due to her calculated behavior of excluding the major obstacle, Heukdan, for Yobai while Si-heon was asleep. Her jealousy is also quite intense. After the Tree Conquest War, when other heroines acknowledged Si-heon's dedication while Jin Dal-rae was sobbing after seeing him, San Su-yu was seen muttering, "Jealousy, so annoying. If I could go back to the past..." as if talking to herself.