Issa appears to be a teenager due to his youthful appearance. He has wildly spiky blue hair and light blue eyes. Regardless of his stature or youthful looks, Issa is relatively muscular, possessing a well-developed array of abdominal muscles.
He is often shown wearing navy blue jacket with yellow insides and keeps the sleeves rolled up. He also wears a navy blue shorts and yellow boots with white straps wrapped around them. He also has two green sleeves with attachable spell notes on his wrists that can also act as shields.
One of his most distinguishing features is his "Dragon Eye", which is located in the center of his forehead. In it's dorment state, Issa's Dragon Eye appears to be a cross-shaped scar. When it awakens, the scars vertically open, revealing a dragon-like eye in the center. The power of Issa's Dragon Eye is so immense, he is forced to wear stone fetters in order to keep his power from running amok.
At first glance, Issa is light-hearted and very lazy. He is usually seen trying to avoid as much work as possible and has shown to have a poor memory, forgotting Kajiyama's name (accidentally calling him Kani-kama) and has forgotton numerous assignments. He has also shown to have a fondness for Ramen, as he once got sick from eating too much and threw up twice before showing signs of improvement.
Despite his apparantly foolish behavior, Issa is an adept fighter and can be very persuasive, able to convince the VIUS squad to let him deal with the monstrous Kaligera alone and outside the city borders.
Though he feigns ignorance of the death of Futaba Sōsei because of the secrecy of the mission he was on, Kazuma regrets withholding his involvement of the event that caused Yukimura to seek revenge.
When it comes down to battle, he is very competent. He wields the broadsword Diamond Sacred Steel and possesses amazing melee skills that appears Dracule-like. Issa, unknown to many of the VIUS, possesses a "Dragon Eye" in his forehead and is forced to wear fetters, spell tablets, which limit his power and keep it contained.
He is able to sense the number and strength of Dracules.