Ofuku

The secondary antagonist of the series. Ofuku is the the godmother of Takechiyo and leader of the faction supporting his claim to the Shogunate. A cold and heartless woman who murdered her husband's mistress and illegitimate child, Ofuku's only redeeming grace is her devotion to her protegé Takechiyo whom she sees as a surrogate son, even risking her own life to save him after the Kunichiyo faction poisoned his tea. Knowing that if Takechiyo falls from power than so will she, Ofuku decides to personally interfere in the ninja war towards the series' end so as to better ensure her faction's victory. Although she orders her samurai to kill Gennosuke Kouga in the final episode, Gennosuke spares her life albeit more out of disgust for her greed and pettiness than any sense of mercy (to him she wasn't even worth the effort). Ofuku is crushed after the Iga's apparent loss and Hanzo the 4th decides to not immediately tell Ofuku how Gennosuke abdicated the Kouga's victory as punishment for her scheming.
From: Wikipedia