Hoshikawa Ryuu is an astronomer whose dream is to make contact with extraterrestrial life. As a descendant of the legendary Iga ninja, he combines scientific curiosity with inherited stealth, agility, and combat discipline.

As Dyna Black, Ryuu brings a tactical and unpredictable edge to the Dynaman team. His ninja background allows him to move quickly, strike from unexpected angles, and adapt to unusual battlefield conditions. He is equipped with Battletector armor, Cross Cutter boomerangs, and Strong Shower webbing, giving him a versatile mix of defense, ranged attacks, and capture techniques.

His Dynarod fires the Black Star Flash, a technique that reflects his connection to astronomy and the night sky. Calm, skilled, and quietly intense, Ryuu fights the Evilution Empire with the focus of both a scientist and a warrior.