Maestro Mangu, known as Gran Mangu in Japanese media and Maestro Nyada in Latin American localizations, is an elderly feline Yo-kai of the Guapa tribe holding S-rank status. He sports orange, brown, and white fur, distinctive purple ears, and green eyes. His aged yet dignified presence includes carrying a small walking stick, wearing a green cape, and bearing purple flames on his tail.

Widely regarded as one of the most formidable Yo-kai, his advanced age restricts the use of his immense power to brief durations. His abilities encompass temporal manipulation for time travel and combat techniques like "Paliza" (Beating) and "Temporal." His ultimate Animaximum move, "Manguerazo," unleashes an infinite energy torrent damaging all opponents. He also possesses "Manga Riega," a defensive skill allowing him to evade and retaliate against all incoming attacks.

His involvement evolves throughout the Yo-kai Watch series. In Yo-kai Watch 2, he becomes a daily opponent atop Mount Piedasolano in Antigua Vellón after completing "The Test of Mangu III" quest. In Yo-kai Watch 3, he automatically allies with the protagonist upon finishing the quest "A Very Real Prank," triggered by interacting with Blanpir from Chapter 4 onward. His role continues in Yo-kai Watch 4, where friendship is secured automatically after clearing Mission 13 of the detective agency storyline, and he also appears at the Yo-kai Gate in Sakura Motomachi.

His design and name incorporate cultural references. "Mangu" derives from a fusion of the Spanish words "Gran" (Great), "Mago" (Wizard), and "Manguera" (Hose). His conceptualization pays homage to Star Wars' Master Yoda, reflecting similarities in wisdom, aged appearance, and mystical abilities.