The upcoming sequel How Not to Summon a Demon Lord Omega will only be 10 episodes long, falling short of a usual 12 episode season.
According to the Tokyo Brodcasting System Program Guide, How Not to Summon a Demon Lord Omega will be full 30 minute series but only last for 10 episodes. Speculatively, this may be so the series doesn’t go passed the manga; as the Zircon Tower arc may take the anime to the end of volume 12 (volume 13 only released in March of this year).
The anime follows Takuma Sakamoto, a powerful player of the MMORPG Cross Reverie. His character, the Demon Lord Diablo has high stats, powerful gear, and an intimidating appearance.
One night he is suddenly transported into the game world in the body of his character, summoned by two young girls who are mages. These are Shera L. Greenwood, a buxom elf and magical archer, and Rem Galleu, a pantheran magician.
Unfortunately for them, Diablo had a ring of spell reflection. The binding spell is turned back on the two summoners. Instead of binding Diablo as a summoned creature, the two girls are bound as slaves to Diablo.
How Not to Summon a Demon Lord is based off the 2014 light novel series by Yukiya Murasaki, Takahiro Tsurusaki, and published by Kodansha. A manga for the series has been releasing since 2015. The first season premiered in 2018.