At some point, the oni created the kanabo to act as a weapon, a power enhancer and a shield for their only weakness, their third eye. As long as an oni held their kanabo attacks on their third eyes would have no fatal effect, though a hit did cause them pain. In lore and in ancient times, an oni's kanabo would take the form of an iron club and the phrase "oni with an iron club" came to mean something's invincible in Japanese. In modern times, the oni reshaped their kanabos to fit in better, in at least one case reshaping it into an ironbound cane.
In 2011, the oni Tora came to Laurel Hill, New Jersey to get his three sons, Dalton Rourke, Ryan Bramble and Jesse Trumball and lead them through the oni rite of passage into adulthood. During his time in Laurel Springs, Tora used his kanabo to enhance the effects of his powers to create deadly catastrophes, also wielding the kanabo as a weapon directly against his enemies. After hunter Dean Winchester was able to kill Dalton with a shot to his third eye, the oni's weakness was revealed and the hunters and local cops began targeting the surviving three oni's third eyes. Though Bobby Singer was able to score a direct hit to Tora's third eye, his kanabo shielded him so that the shot only caused him pain instead of killing him. Following the incident, the hunters realize that removing the kanabo from Tora's possession will enable them to kill him. During the following assault on Tora's hideout, Dean attempts to get close enough to knock the kanabo from Tora's hand with a steel crowbar to no avail. After the appearance of an obake distracts Tora, Sam Winchester shoots the kanabo with an armor-piercing round, causing no damage but making Tora instinctively pull it closer to his body and thus closer to Dean. With hard blows from his crowbar to Tora's hand, Dean is able to force the oni to drop his kanabo, leaving him vulnerable to attack. Bobby then immediately shoots Tora in his third eye from a distance with a rifle three times before he can reclaim his kanabo, killing him. Its unknown what the hunters did with the kanabo following Tora's death.