Is Onmyou Taisenki hentai?
English title: The Chronicle of the Big Battle between Yin and Yang
No
Rated PG-13 (Teens 13 or older) on MyAnimeList and not tagged as Hentai.

TV · 2004 · 52 episodes · PG-13 - Teens 13 or older
Adventure, Fantasy, Shounen
Riku Tachibana is an average 1st year junior high school student who was supposed to be living a peaceful, ordinary life, but just after entering junior high he ends up fighting a duel against a mysterious man calling himself “a Warrior of Earth,” and Riku’s life is changed forever! Riku discovers that he is a survivor of the believed extinct “Warriors of Heaven,” Using a device called “DRIVE” and summoning a Shikigami, or “Divine Beast,” called Kogenta to his side, Riku devotes his life to the battle against the Warriors of Earth! (Source: Sunrise)
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