Haiga is a relatively short (only taller than Tokunosuke and Hikaya) boy with light green hair and yellow eyes, wearing a standard Heartland Middle School uniform. His skin, however, is deathly pale, and his eyes look sleep-deprived. While he has his Number, he uses a D-Gazer tattoo formed from his illness particles, turning his eye pink and gaining black markings.
Haiga has a surly disposition due to his illness, having a dislike of healthy people, thinking they are looking down on him when they try to get him treatment. This also leads to some arrogance on his part. In reality, he is scared of ending up living a pathetic life as a result of his illness.
From an early age, Haiga was diagnosed with an incurable illness, and was looked after by his nurse, Eiko. Though he initially followed doctor's orders, at age nine, Haiga found books detailing the horrific conditions and prejudice against sick people in past times. Shocked and scared, Haiga immediately stopped following doctor's orders and refused treatments, forcing himself to go to school and have a normal life. However, people avoided him and teased him, causing Haiga to become surly and anti-social. His illness turned out to be contagious, causing multiple kids he interacted with to become sick.
Haiga first appears near Yuma and his friends during lunch, putting them off before being approached by Eiko, but he completely refuses her help. In class, he passes out due to his illness, but awakens with no attitude change. A letter arrives for him, but it turns out to be Number 37, which corrupts him. Escaping from the infirmary, Haiga returned to school the next day and infected various students with his power, including Sachi, Hikaya, Yuma, and Tetsuo. He was eventually discovered and challenged by Kotori. During the Duel, Kotori pleads to Haiga to stop, claiming that times have changed since the old days, but Haiga refuses to stop. Haiga was eventually defeated, losing his Number and his powers, and was returned to the infirmary. Upon waking up, Haiga regrets his actions and realizes what Kotori was trying to tell him, thanking her for his help before getting some well-deserved rest.
While Haiga possessed Number 37, he had the ability to produce pink particles that could make anyone that came into contact with him greatly sick.
- Haiga is possibly of Turkish descent, as he says "Kahretsin!" ("Damn it!" in Turkish) once during his Numbershot.