Sengoku Boryakuzu

The son and heir of Kuroda Kanpei, a military strategist who served Oda Nobunaga and Toyotomi Hideyoshi, was killed by Nobunaga and Hideyoshi while Kanpei was imprisoned by Araki Murakeshige. Kanpei, bent on avenging his son's death, now plotted against the two men whom he had served. Even though Nobunaga was eventually killed by Mitsuhide, Hideyoshi turned this misfortune into a blessing to succeed Nobunaga and conquer all of Japan! (Source: LEEDS, translated)