Is Black Clover: Jump Festa 2016 Special hentai?
No
Rated PG-13 (Teens 13 or older) on MyAnimeList and not tagged as Hentai.

OVA · 2016 · 1 episodes · PG-13 - Teens 13 or older
Action, Comedy, Fantasy, Shounen
An OVA episode bundled with the 11th manga volume.
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