Kikai Sentai Zenkaiger S01E07 - The Prince of the Demon World Is Short-Tempered!

The mysterious individual reveals himself as Stacey, Barashitara's son, and confronts the Zenkaigers directly. Armed with his own version of the heroes' equipment, he transforms into Stacaesar and uses the powers of their Super Sentai predecessors and their mecha against them. All the while, Gaon struggles to determine whether the human-like Stacey really is human or a Kikainoid.