Ogen a character featured in the Japanese anime Basilisk Kouga Ninpou Chou (known in English as Kouga Ninja Scrolls). As the leader of Iga Tsubagakure, Ogen was ordered by retired Shogun Tokugawa Ieyasu to lead nine other warriors in a duel against the chosen ten of the rival Kouga Manjidani clan to determine a successor to the shogunate.

An old woman at Basilisk's start, Ogen has a spiritual connection to her hawk which serves as her messenger and servant. It is not known though if she possesses any other abilities. When she was younger, she was very much in love with Kouga Danjo and the two sought peace between the warring clans through their marriage. But following a surprise attack by the combined forces of Oda Nobunaga and the Koga in which her grandfather was murdered, she lost all faith in Danjo.

Despite the Koga's betrayal, Ogen was in her twilight years willing to make her granddaughter Oboro the bride of Danjo's grandson Gennosuke in the hopes that the two of them could bring a definite peace between their clans and also find the happiness she could not. In the manga, Ogen's first candidate was her subordinate Yakushiji Tenzen, yet in the end she preferred Gennosuke as Oboro's future husband.

In the Japanese original anime, she is voiced by Hisako Kyouda.

 

Ogen VS Danjo (episode 1): The climax of Ogen and Danjou's relationship. After meeting with Tokugawa Ieyasu at Sunpu and deciding the twenty ninja to face each other in the battle to determine a successor for the Shogunate, Danjo and Ogen discussed along a river's bank how fate has decreed their two clans can never exist as one, despite their wishes and those of their respective grandchildren. With Ogen's attention preoccupied with past memories, Danjo seized the opportunity to fire a poisoned needle through Ogen's throat as he revealed that he had stolen the scroll her underling Yashamaru was supposed to deliver to Tsubagakure. He then bit his finger to mark out Ogen's name in his own blood before shooting a second needle into her mouth, piercing the back of her neck and supposedly killing her.

As Danjo said his final goodbyes to his former lover, Ogen's hawk distracted him with a loud shriek, allowing the mortally wounded Ogen to stab Danjo through the back with the very needle he used to strike her down. Danjou fell over dead, and Ogen cackled vindictively as she leaned over his body and crossed out Danjo's name with his blood. But as the life faded out of her, Ogen's malice melted away and she wept in misery as she finally realized it was her and Danjo's lack of trust in each other that was what ultimately brought them to this point as well as the suffering Oboro and Gennosuke were now bound to experience. Not fate as they had originally surmissed.

Unable to go on, Ogen collapsed on Danjou's body and the two of them floated away into the river. Ogen's last action before entering into the afterlife alongside Danjo was to summon her hawk to carry the Iga's scroll to them so her clan would have a fighting chance for survival in the coming war.

In the manga, Ogen's backstory regarding her relationship with Danjou is hardly touched upon and it is suggested the reason their love ceased was due to pressure from their respective clans to end the affair.

Ogen in the manga also tends to view Oboro as a disappointment to the clan and is hinted to have only consented to her marrying Gennosuke due to her grandaughter's lack of fighting skills. In contrast, Ogen in the anime was more forgiving of Oboro's faults and even attempted to boost her self-esteem when she failed in her training by saying she preferred her as sweet and loving. She also took pains to hide the Koga's actions following Nobunaga's surprise attack so Oboro wouldn't become infected with the Iga's hatred.