|Likes||Women, Delicacies, Ramen|
|Quotes||"Such Pieces of Trash"|
Oni Aliens (????, ?????-Seijin) are a race of aliens that have taken refuge on the earth and therefore have become targets of a global alien extermination effort.
The hunt for the Oni Aliens was a major turning point in the story. For the first time in the series, the target aliens were visible to normal humans. As the hunt neared its conclusion, even the Gantz hunters themselves became visible. Also, the timer displayed by Gantz simply turned off in the middle of the mission, effectively giving the hunters unlimited time to complete it.
Like the Chibi aliens, the Oni aliens appeared to be completely sentient and intelligent, they acted and dressed like humans, used cell phones, and even enjoying human entertainment, suggesting that they lived among humans in human guise rather than hiding as the other previous aliens had. They were also quite aware of Hunters' existence and the weaknesses of the suits.
The boss of the oni aliens was a powerful alien who, once reverted to his true form, demonstrated incredible strength, speed, and the unique ability among his kin to launch powerful electrical discharges. He was also suggested by the Vampires to be the strongest of their group, making short work of a majority of the Tokyo team in a matter of minutes as well as decimating many of onlookers. He was preceded by three other oni aliens that also demonstrated unique abilities: one could turn his body to flames and create balls of fire; one could transform his entire body to stone in order to augment his offense and defense; one could freely control the form of his body, easily taking the form of human and animals alike for the guise of disguise and attack.
It was also the first time the aliens were waiting for the arrival of the Gantz players, and had gathered in enormous numbers in order to finish the Hunters once and for all. The average Oni alien was capable of assuming human form. Their true forms were humanoid but with long tentacles in place of arms, sword-like claws, elongated necks, and an acid spit that easily penetrated the Gantz suits' defenses. They also had short horns that made them not unlike the traditional Japanese folklore depictions of Oni.