How Not to Summon a Demon Lord, also known as The King of Darkness Another World Story: Slave Magic (Japanese: 異世界魔王と召喚少女の奴隷魔術, Hepburn: Isekai Maō to Shōkan Shōjo no Dorei Majutsu, transl.

"The Other World Demon Lord and the Summoning Girl's Slave Magic") is a Japanese light novel series written by Yukiya Murasaki and illustrated by Takahiro Tsurusaki.

Takuma Sakamoto is a hikikomori gamer who is mysteriously transported to the virtual world of his favourite MMORPG, Cross Reverie, with the appearance of his own character in the game, the Demon Lord Diablo.

With a serious case of social anxiety, Takuma decides to act like his character while interacting with others, and makes use of his high stats and vast knowledge of Cross Reverie's lore to survive in his new environment, traveling along with Rem and Shera to look for a way to remove their slave collars, while helping them with their own personal issues that led them to summon him in the first place.

[21] The series aired from July 5 to September 20, 2018, and was broadcast on AT-X, BS Fuji, Tokyo MX, and Sun TV.

[2][7] The series' opening theme, "DeCIDE", was performed by the unit SUMMONERS 2+, a group composed of voice actresses Azumi Waki, Yū Serizawa, Yumi Hara, Rumi Okubo, and Emiri Katō,[4][22] while the ending theme, "Saiaku na Hi demo Anata ga Suki."

[28] On April 8, 2020, it was announced that the series would receive a second season titled How Not to Summon a Demon Lord Ω, co-animated by Tezuka Productions and Okuruto Noboru, and directed by Satoshi Kuwabara, with the rest of the staff and cast members reprising their roles.