Obtained from The Demon King's Castle of Hell Event.
A strong Sub for any Red Attack card, Mitsuhide grants a 30-40% Skill Boost and +1 ATK. But for every +1 ATK, the Minimum Skill Boost is increased by +1%, allowing Mitsuhide to eventually become a 35-40% Skill Boost at +5 ATK. That said, he'll work well on any Red Attack card you happen to have.
[Akechi Mitsuhide] was a samurai and general who lived during the Sengoku period of Feudal Japan. Mitsuhide was a general under Oda Nobunaga, although he became famous for his rebellion against Nobunaga in 1582, which led to Nobunaga's death at Honnō-ji.