The Younger Sister is the War God ~The Unification of the Realm by Nagao Harukage~

"Uesugi Kenshin," a warlord that anyone who likes the Sengoku period would know about. Whenever the topic of the strongest in the Sengoku period comes up, his name is always mentioned. However, even for someone like Kenshin, unifying the realm is quite difficult. The protagonist is reincarnated by Bishamonten because they want Uesugi Kenshin to take over the realm—but the reincarnation destination is not Kenshin, but his older brother!? Moreover, Kenshin is female!? This is a Sengoku reincarnation story where the protagonist, caught between a father strong in war and a younger sister, mainly works hard on domestic affairs and scheming. While there are parts where the author's knowledge is questionable, I hope you will join me in this story.