Samurai:

Oda Nobunaga made innovations in the fields of organization and war tactics, heavily used arquebuses, developed commerce and industry and treasured innovation. Consecutive victories enabled him to realize the termination of the Ashikaga Bakufu and the disarmament of the military powers of the Buddhist monks, which had inflamed futile struggles among the populace for centuries. Attacking from the "sanctuary" of Buddhist temples, they were constant headaches to any warlord and even the Emperor who tried to control their actions. He died in 1582 when one of his generals, Akechi Mitsuhide, turned upon him with his army.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". Who caused Oda Nobunaga's death?
Akechi Mitsuhide