Yi Sang is a man of average build and pale complexion. He has short black hair which frays slightly at its ends, and dead-looking black eyes adorned with heavy eye-bags underneath. In this scenario he wears a “bunny suit” (one of those sexualized ones that are used for smut purposes, the ones where the individual wears bunny ears (not real ears, just the attachable ones like that of headbands), netted leggings, and a suit that stretches to the upper chest/breast area). He also wears specific white gloves and high heels as well I guess. Also a bunny tail, don’t forget that.

Yi Sang is a particularly quiet, mellow man. At the beginning of the game, he fails to stand out much among his fellow Sinners due to his tendency to stay silent and watch rather than actively contribute to discussions. When he speaks, his words are often obscure and riddle-like with a monotone delivery, and his expression rarely changes.

In Canto IV: The Unchanging, more is revealed about Yi Sang little by little, such as his extremely low self-esteem and suicidal thoughts. After his initial confrontation with Dongbaek, Yi Sang confesses that he considered the day he met Dante and gained immortality against his will to be his greatest moment of despair, as he instead quietly wished for his own eternal rest. Following this interaction, Dante resonates with Yi Sang's mental state, where they see Yi Sang with a large, cracked void in his chest with no signs of mending. It comes to light that the disbanding of the League of Nine Littérateurs, which had provided him with comfort and safety amidst the chaos of the world, had ultimately left him grief-stricken, hopeless, and alone. In his depressive state, Yi Sang was the type to grow slothful, finding it easier to go along with what other people wanted of him rather than deciding for himself.

He also displays a strong sense of morality for a City citizen, disgusted at Dongrang's callous behavior concerning the death of his fellow K Corp. employees and saddened by the Wings' exploitations of their people. Later, he is similarly upset to see Aseah utilizing his Mirror Technology to experiment on humans. Here, Yi Sang is unsettled by N Corp.'s unethical use of his discoveries and the group's plans to manipulate Nelly and Catherine into the creation of the laboratory, believing the resulting experiments to be too high a price when compared to any human life.

By coming to terms with his own past and a newly found sense of hope, he becomes much warmer and open towards Dante and the rest of the Sinners post-Canto IV. Although not as outspoken as Sinclair, Yi Sang tends to encourage kindness and mercy where possible, and often brings up his own regrets over losing his colleagues to advocate against conflict.

Despite Yi Sang's position as a genius, he's also proved himself to be rather socially awkward and naive. He is often distracted by things he finds intriguing, fails to understand jabs, and takes things literally. One case appears in Canto VI: The Heartbreaking: after mentioning the odd circumstances around the mission, Ishmael and Hong Lu jokingly accuse him of making fun of Heathcliff and the love letter he received, whereas Yi Sang earnestly and panickingly clarifies he didn't mean to insult his fellow Sinner. In general, Yi Sang has come to show much more of himself with time, including quirks and flaws. However, the wider range of his personality just goes to show that Yi Sang is in a much healthier place than he once was, as he is now determined to live moving forward alongside a new set of companions.

Well this time he’s just kind horny as well in this.