Recently, a fan tweeted an English fan translation of an Overlord bonus short novel titled Boukoku no Kyuuketsu-hime.
So yeah, it does seem that the Overlord creator really doesn’t like fan translations.
Japanese author Kugane Maruyama has introduced us to the world of Overlord, and he’s been regularly communicating with fans through twitter.
It is possible that Maruyama was applying this principle to fan translations, implying that freely distributed translations would drive the official product out of existence.