Oyu (小谷のお邑, Odani no Oyu) is a character from the Onimusha series. She is featured in Onimusha 2: Samurai's Destiny, Onimusha Blade Warriors and Onimusha Soul. Her life becomes intertwined with that of Jubei Yagyu, even though she is based on the historical figure, Oichi, who never met him. Ohatsu from Onimusha: Dawn of Dreams is her daughter.
A fencer who wears western style armor and wields a western sword and a circular shield. Oyu of Odani is beautiful, but melancholy and her past is shrouded in mystery. She was historically the sister of the infamous Nobunaga. She did join in the fight against her overlord brother (as in the game), but with her husband Nagamasa Azai rather than Jubei, and later joined Hideyoshi Toyotomi when he rose to power.
In the game, she is first seen by Jubei in the town of Imasho. Later, he finds her in the clutches of Tokichiro (the future Hideyoshi) and rescues her (however, her daughter Yodo will later go on to become his concubine and the mother of his heir). Nearly at the end, she is revealed as Nobunaga's sister and, in fact, joins the fight in order to secure her husband's territory.
If certain conditions are met, Oyu becomes playable at one point in the game. She can then access places and obtain items that are exclusive to her character.
- Broad Sword - Oyu's default weapon is a medium-length, double-edged sword with sufficient weight and damaging capabilities.
- Phirangi - The Phirangi can be wielded by Oyu if Jubei purchases this item from the Imasho Town shop and gives it to Oyu through Gift Exchange. The Phirangi is longer and sharper than the Broad Sword, providing a greater attack range and damaging power.
- Gradius - Oyu finds the Gradius during the brief time in which she becomes a playable character. It is located next to the Magic Mirror at the bottom of Fog Bridge. The Gradius is a legendary weapon from the West, a medium-weight sword with a tremendous sharpness that is the ultimate weapon for the female warrior.
- Dagger - By pressing L2, players can make Oyu toss a lightweight throwing knife. She begins with 30 Daggers in her possession, and she can find more when they are dropped by her defeated foes. Throwing Daggers is a great way to attack enemies from great distances. Players can use them to delay or forestall the attacks of larger foes by causing them to stagger in pain.
- Lion's Heart - (only in Blade Warriors) - It is said that an English king was the owner of this sword.
- Chinese Combo - (only in Blade Warriors) - A rock-solid wok and ladle used for cooking Chinese cuisine.
- Bamboo Sword - (used only in Blade Warriors) - When a famous swordsman trained with this blade, it helped him master his art. Also used by Samanosuke, Jubei Yagyu and Nobunaga.