Yama-Oroshi is a giant man-eating bear appearing on Yakuza 5 and an enemy of Taiga Saejima. First serving as a main storyline boss, it also serves as the main antagonist of Saejima's hunting storyline.
Yama-Oroshi is a giant bear, lurking around the Hunting Village for several years. 10 years before the game's time, Okudera who by the time went by the name Kiyoshi Sato and the real Okudera where hunting and got ambushed by the beast. The bear left the real Okudera fatally wounded, with Sato taking the name Okudera from that moment as per the request of his dying friend.
During the following year, several hunters would come to the mountain taking the chance to amass money from poaching before the Bill for Hunting Law was approved which would prohibit excessive hunting. The massive hunting practice changed the ecosystem forcing the Yama-Oroshi to descend from the mountain to attack humans for food. The vicious bear would assault the village, and while the villagers manage to survive, the beast destroyed their houses and ravaged their food stocks, which almost killed the village out of starvation. The incident caused the villagers to shun Okudera and left them with a traumatic experience that caused them to become distrustful and less co-operative, although in truth they shunned him down in order to protect him as the village knew he was a escaped convict, therefore so long as they knew little about him they would be unable to report him to the police The incident sparked Okudera to hunt the beat for several years but without success. Unknown to Okudera the villagers would watch him from afar. The beast nonetheless got a fearsome infamy that spread across several parts of Japan that even Himura got caught ahold.
Nine years later the beast encounters Taiga Saejima after he is knocked out of his snowbike when he got distracted with Shigeki Baba's sudden collapse. Saejima is surprised that the beast is larger than Himura described and without a chance at escaping decides to brawl with the beast for his life. Saejima is able to injure the beast to the point he caused it to desist but left him exhausted to be found by Okudera.
Saejima encounters the beast once more after following Okudera who was looking for Baba on his behalf. Baba is found injured, suggested the Yama-Oroshi may have managed to get to him before but being unable to kill him. Okudera distracts the bear while Saejima carries Baba back to the village with Okudera barely managing to survive. Okudera reveals that contrary to all his other preys, he is not chasing the Yama-Oroshi for hunting purposes, but rather to murder it.
During one of the many hunting trainings sessions Saejima and Okudera encounter the beast once more, who chases after them and manages to injure Okudera but ceases chase after. The injuries of Okudera are grave enough to force Saejima to look for Bear Bile to heal him, and is left resting for a long period.
Eventually a hunter called Narumi comes from the outside, hearing rumors of the bear and attempt it to hunt it for glory and money. The arrogant hunter believing he can defeat the beast by himself and looking down on the villagers' fear, decides to perform a dangerous scheme by spreading Bear Bait all around the mountain, prompting several Bears to wake up from their hibernation and putting the village at risk of another assault. Saejima offers himself to gather all the bait on the village's behalf and after completing this endeavour he is witness to Narumi facing the bear. Although the hunter manages to get two shots on the bear, these attacks are ineffective on the Yama-Oroshi, causing the giant bear to retaliate by biting Narumi and tossing him aside violently. Saejima is forced to retreat to the village but after recovering, decides to search for the injured Narumi whose wounds are severe enough to require medical treatment and leaving him with an inability to hunt again but left Saejima with a parting gift in the form of bullets with special trackers on it that could be used to trace the Yama-Oroshi but they would have to be shot on the underbelly as it was the only vulnerable spot.
Saejima eventually faced the beast and placed the tracker and subsequently make his return to the village. Saejima and Okudera would trace the beast back at the ends of the mountain beyond a broken bridge, by request of Okudera the two return to the village. However Okudera would trick Saejima into going to the village while he himself went to hunt the bear alone. Saejima would follow on a snowmobile only to find Okudera injured and almost killed by the bear.
After this the Yama-Oroshi would be sighted near the village causing Saejima to offer himself to face the menace. Sakurai and Nishina learning of Saejima's background would decide to stay on the village in order to not report him as a criminal. Saejima would hunt the beast and put a few shots before being stricken by the bear and tossed aside. Without his rifle Saejima was forced to brawl once again with the giant bear, barely succeeding at defeating it. Sakurai and Nishina would decide to help Saejima despite their initial stance and would warn him that the police was coming and that they were planning to mislead the authorities like they did with Okudera.
Okudera himself would overhear the conversation and reveal his past a Yakuza-affiliated assassin sent to kill the real Okudera but decided against it at the end as he saw the real Okudera as a friend and that the real murderer was the bear itself. Nishina encouraged Okudera to finish his struggle with his longtime enemy but Okudera sticking to his principles as a hunter decided against kill the bear as it would be slaughter that would turn him back into a murderer. The group respecting his wishes return to the village with Nishina misleading the police and the bear retreating from the village outskirts to not be seen again, thus ending its reign of terror for good.
- Demon Bear shares the same model as Yama-Oroshi.