One of the Irregular Hunters, B-Rank. He is friends with Zero, Axl, and Guest. He is kind-hearted and energetic, but can be quite quiet around people he meets for the first time. His weapon is the X-Buster (a weapon that retracts his hand into his forearm to reveal a muzzle, firing bullets of condensed solar energy).

One of the three Irregular Hunters, S-Rank. A robot with a refreshing yet stiff and cool-headed personality. He is friends with X, Axl, and Guest. His weapon is the Z-Saber (a laser sword).

One of the three Irregular Hunters, B-Rank. A friend to X, Zero, and Guest. He is energetic and cheeky, serving as the mood maker of the group. His weapon is the Axl Bullets (dual pistols).

A villain with a wicked personality. He is the king of the Irregulars and controls them. He is currently spreading his influence through hacking chips.

Due to an abnormality in his electronic brain, he disregards all means and consequences to destroy Irregulars. Rather than eliminating threats, he seems to enjoy the 'hunt.' He is a being barely distinguishable from an Irregular himself. Because of this, he was removed from duty and detained. He has a cold and eccentric personality.

A gentle and kind assistant to the Irregular Hunters. She is a supporter and does not participate in combat. She tends to speak politely. She and Zero have feelings for each other, but neither is aware of the other's heart.

An operator and navigator at the Irregular Hunter Headquarters. She is in a relationship with Gate, though they bicker often. She has a kind and compassionate personality.

A researcher at the Irregular Hunters who serves as the head of the laboratory. He is dating Alia, but they occasionally clash. He has an arrogant and cynical personality.

The current Commander-in-Chief of the Irregular Hunters, who took over the position after the previous commander resigned following a past incident.