Historically, she never met Jubei, but she did join in the fight against her overlord brother with her husband - Azai Nagamasa rather than Jubei, but she later joined Toyotomi Hideyoshi.
Onimusha 2: Samurai's DestinyEdit
In the game, she is first seen by Jubei in the town of Imasho, where he fends off three men whom are hitting on her before heading to the Imasho Mines. Jubei later finds her in the clutches of Tokichiro (the future Toyotomi Hideyoshi) and rescues her (however her stepdaughter Yodo will later go on to become his concubine and the mother of his heir). Jubei joins Oyu's fight to secure the territory of the Azai. Oyu then assists Jubei in his battles against Nobunaga's armies as well.
Over the course of her journey, Oyu begins to fall for Jubei, as seen on their ride back to Imasho on the Oni Horse and other instances. Oyu is always present to assist Jubei whenever she can, a sign of her latent affections toward him. Oyu is also emotionally conflicted between her duties and her feelings for Jubei as the story progresses.
When both she and him are trapped by Tokichiro in an underground pit, she reveals to Jubei that she is actually Oichi, wife of Nagamasa Azai and the sister of Nobunaga. Oyu then explains her reasons for being caught at Gifu Castle: she planned on assassinating Nobunaga, due to his malicious intentions of destroying the Azai clan and conquering Odani. Oyu also reveals to Jubei that she felt betrayed when she learnt from Nagamasa - two years after they were married - that he already had three daughters from his previous marriage.
Oyu then tells him that nothing mattered to her after that until she met Jubei. Oyu then thinks of herself to be selfish because of her statement and becomes set on returning to Odani in order to protect her stepdaughters. Overcome with emotion, Oyu embraces Jubei and the pair almost share a kiss, but Tokichiro interrupts with a blast to the pit, opening yet another path to lead them out of their prison. Oyu falls into a hole, and struggles to escape, when Gogandantess unexpectedly rescues her stating "It is quite natural for men to rescue weak women." After Jubei defeats Gogandantess, the both of them escape the island, making it onto Tokichiro's flying airship, the Oni Genbu.
Jubei and Oyu soon wipe out Nobunaga's armies near Odani Castle using the Oni Genb and then return to Gifu Castle where her brother was located. Oyu and Jubei are then separated when the Oni Genbu crashes into Gifu Castle. Jubei jumps out safely, but Oyu does not, making Jubei believe her to be dead.
Before heading down to face Nobunaga, Jubei and Oyu reunite for the last time. With very few words exchanged, Jubei then convinces her not join him on his final battle against Nobunaga, reminding her that he is still her brother and cannot be involved. Oyu stops him before heading inside the elevator, trying to confess her feelings to him, but just smiles sadly at him. Jubei then pulled her to him and they finally share a memorable kiss before he departs to face Nobunaga. The last words Jubei said to her were "I hope you find happiness." Oyu is then left at the elevator as she watched Jubei descend to her brother's lair. After he disappeared from sight, she collapses and cries, eventually returning to Gifu Castle.