A day-to-day treasure hunter. Well-versed in ancient scripts, he deciphers old manuscripts and sets off on expeditions, excavating ancient relics while wearing a protector suit he developed himself. His destiny begins to shift drastically after excavating the Omega Horn used by an ultra-ancient Captain and meeting Enkaku. He grows as he battles and interacts with various Horned Beast Hunters. He transforms(?) into Captain Omega Horn using the Omega Analyzer. His speech is casual and masculine (ending in "da/na"). He often acts alongside Eiru, Aru, and Giriko. He is almost always with Enkaku.

The ancient King of Horned Beasts who was sealed in the Egorgia found by Shout. While his true form is that of a giant beast, he usually stays with Shout in a human-like form (Demi-Beast Form). He carries himself with the dignity of a king, but having slept within Egorgia for so long, he is ignorant of modern civilization. He sees the quality of a king, "Ego" (a heart that follows its own path without wavering), in Shout and urges him to fight alongside him under the name "Captain Omega Horn." Though they clash at times, he guides Shout toward becoming a true Captain. He often acts with Eiru, Aru, and Giriko. He is almost always with Shout.

A Horned Beast Hunter of the same generation as Shout. She takes an interest in Shout and his partner Enkaku after they find the Omega Horn, appearing wherever they go. She has a shrewd personality, sometimes acting as an ally and other times as a rival. She specializes in fighting with a greatsword by possessing herself with the power of "Zankaku" (Slash-Horn). She wears a purple midriff-baring top and black shorts, carrying a purple greatsword modeled after Zankaku. She often acts with Eiru, Aru, and Shout.

A Horned Beast Hunter wearing glasses and a school uniform. She has a strong sense of justice and takes a firm stand against any Hunter who misuses their power. On the other hand, she is high-spirited and ambitious, dreaming of becoming famous so that work floods in and she can become a "billionaire." To achieve this, she boldly challenges Hunters from giant organizations like the Ibal Union Zetsu, aiming to build up her achievements and experience. She generally plays the role of leading her shy younger brother. She often acts with Giriko, Aru, and Shout.

Eiru's twin brother. A rookie Hunter Shout meets during his journey. He is shy but very knowledgeable about Horned Beasts. He summons the Horned Beast "Gokaku" (Strong-Horn), which can split into two creatures, and fights with perfectly synchronized combinations. He aims to become a Horned Beast Doctor. He often acts with Eiru, Giriko, and Shout.

The charismatic leader of the Ibal Union, possessing overwhelming power and commanding many Hunters. Driven by his own intense "Ego," he dispatches Hunters to neighboring countries to expand his territory and seize control of the world. Ibal himself is a combatant, engaging in battles using a special Horn-Awakening Tool and the power of Zetsuenkaku. He uses the Omega Horn Zetsu.

Possesses absolute self-confidence and an aura of strength that belies his appearance. Unlike other Hunters and beasts serving Ibal, he treats Ibal as an equal. Like Enkaku, he usually stays in a human-like form (Demi-Beast Form). He is Enkaku's younger brother.

Usually sealed within the Dankaku Egorgia. A Horned Beast that awakens the power of bullets. Its five heads each have a different number of horns. When one head unleashes a technique, the other four mimic it. This is Guest's Horned Beast. Special Horn Move: Dankaku Shot Fires a rapid barrage of high-speed bullets. When performing a Horn-Awakening Possession, a magenta and black Gatling gun with five muzzles appears.