Oni no Sakuza

From MangaHelpers:

Starting in 1590, this historical manga features the deadly Sengoku-period samurai Honda Sakuzaemon Shigegetsu, known as Oni Sakuza for his ferocity. He fights for Tokugawa Ieyasu, along with the warrior Ookubo Hikozaemon Tadataka. Tokugawa's forces, along with the forces of Toyotomi Hideyoshi (a very recent ally after Tokugawa opposed him in the Komaki Campaign), are attacking the last independent daimyo, Hojo Ujimasa, who ruled 8 provinces in the eastern Kanto region of Japan. Sakuza is still suspicious of this new ally, and still considers anyone not Tokugawa an enemy! [tethysdust]