Tensei shitara Zense no Otoko Tomodachi ni Kyuukon Saremashita

Two young men were fast friends and fought side by side in the Warring States period, until one fell in battle. They vow to renew their friendship in another life, and centuries later, they are reborn in present-day Japan, now as a man and a woman. What complex feelings will they carry upon their eventual reunion?

(Source: Kodansha, translated)