Sing is a very short young man with cropped dark blue hair and thin eyebrows above his dark eyes. His usual casual attire is a white tank top tucked into jeans with a belt. He has a slender build and is younger-looking than most others, standing as the second youngest character besides Ash to be a gang leader.
Sing is determined and ambitious, a good leader and to the point. Although he has impressive leadership skills, his older brother Lao worries about him being in charge of a criminal gang. He is very loyal to his gang and street gang conduct. He is also forward-thinking and smart, being able to think matters logically while keeping his nice nature at heart. Sing is not afraid to speak his mind and to tell others what he thinks, regardless of whether it annoys others or makes sense. He is one of the more compassionate characters, showing concern for the well-being of people he does not like or even know such as helping Eiji. He has to act tough, being the leader of Chinatown, but at heart he's still childlike and carefree. He thinks nothing of resorting to violence and is a skilled fighter. Ash is the only person who has ever survived Sing's attack with his deadly weapon, the 'Flying Dragon Fang.'
With Shorter gone, he assumes the leadership position of Chinatown; Once Ash's gang states they do not want war, he arranges for a plan to rescue him.
The two are never shown in a scene together, but it is implied that they were close and that Sing showed great respect for Shorter. Sing expresses a great deal of anger and frustration about Shorter's death, and is persistent in wanting to know the truth about how he was killed. He also is shown to miss having Shorter's guidance, sitting next to an unconscious Lao and asking, "What should I do, Shorter?", later telling Lao that he wishes he had not become a boss and that Shorter was still with them.
He is Sing's half brother. Yut-Lung captures Lao and manipulates him into betraying Ash by telling him that he can save Sing if he does so. Lao and Sing care deeply for each other, but Lao leaves Sing's gang because he does not want to work with Ash due to his resentment of him for killing Shorter ignorant of the circumstances.
His first view of Ash was as an enemy, only knowing that Ash was the one who shot Shorter but not knowing the reason behind it. In their first encounter, they fought with each other, where Sing lost and left the fight. Over time and after discovering the real reason why Ash had to kill Shorter, the two become allies. Sing is shown to admire and respect Ash to the point of hero-worship, as well as trusting and acknowledging him as a good leader.
In "Garden of Light," Sing describes Ash as "so beautiful you could hardly believe it." In the manga "Yasha", a now-adult Sing still speaks both highly and fondly of Ash.
Though they met in complicated situations, Sing and Eiji were very quick to become friends. Sing rescued Eiji from some street thugs and took him back to his hideout after he had collapsed. His trust in Eiji increased when Eiji told him about Banana Fish and the truth about Shorter's death. They work together many times and Sing comes to care for Eiji's well-being.
In "Garden of Light," Sing has his own room in Eiji's apartment. They have shown to have become extremely close, having a strong connection over the events of Ash's death. Sing may have developed some feelings for Eiji over time, or he may be keeping close over lingering feelings of guilt, as his name itself means "guilt" in Chinese, a fact he points out to Eiji and Akira.
Though never having met, he at once complies with Yut-Lung's request that he abruptly leave with him via helicopter on account of his Lee family affiliation. Sing considers Yut-Lung to be similar to Ash in some ways, but is aware of his reputation as a particularly poisonous snake. Sing tells Yut-Lung that he does not dislike him, but sides with Eiji and Ash because he disagrees with Yut-Lung aiding Dino and trying to murder Eiji.
In "Yasha", Sing and Yut-Lung are implied to be close, as they both head the Chinese mafia.
He first meets Blanca and instantly notices his huge height compared to him, and tells him to move as he is blocking out the sun. They fight together against Colonel Fox's mercenaries.
They interact on the same level as gang leaders with Sing positioning himself as his counterpart overseeing the fight with Ash and Arthur alongside Cain. They work together to help Ash against Golzine.
He first meets Shunichi Ibe's niece, Akira, in Garden of Light. They become friends, despite an age difference of ten years, and Sing remarks to Eiji that he thinks she's "a sweet kid". Five years later in New York Sense, their wedding pictures are shown, signifying they have married. In Yasha and Eve no Nemuri, they are still happily married and have a teenage son.
- Episode 09 Save Me The Waltz
- Episode 10 Babylon Revisited
- Episode 12 To Have and Have Not
- Episode 13 The Snows of Kilimanjaro
- Episode 14 Tender is the Night
- Episode 15 The Garden of Eden
- Episode 17 The Killers
- Episode 19 Ice Palace
- Episode 20 The Unvanquished
- Episode 21 The Undefeated
- Episode 22 As I Lay Dying
- Episode 23 For Whom the Bell Tolls
- Episode 24 The Catcher in the Rye
Sing carries around a weapon called the 'Flying Dragon Fang.' It is a kunai like weapon that can be thrown to stab into a victim and with the wire that is attached to it, wrap around and bind them.
- (To Eiji) If the former boss gets hit then it's the duty of the new boss to make the drop.
- (To Lao) Ash asked me to look after them.
- (To Lao) If we don't fight back now, we'll forever be expendable tools.
- His name means 'demon,' 'lion' or 'guilt' 
- He also appears as a supporting character in Akimi Yoshida's manga Yasha.