The Demon Lord Act

The Demon Lord Act is the first episode of the How NOT to Summon a Demon Lord series. It aired on July 5, 2018.

Synopsis
''At MMORPG Cross Revelation, Takuma Sakamoto boasted the overwhelming strength to be called demon king. One day he is summoned to a different world in the form of Devil Diablo in the game. There were two girls, Shera and Rem, who insisted that "I am the summoner." They can make slave magic for summoning beasts from them, but the unique ability "magical reflex" is activated! It was the girls who turned into slaves ......''

In Order of Appearance

 * Takuma Sakamoto/Diablo
 * Rem Galleu
 * Shera L. Greenwood
 * Mei
 * Celestine Baudelaire
 * Galluk

Differences from the Light Novel

 * The episode teaser, which covers the Prologue and bits of Chapter 1 of the first Volume, has Takuma narrate instead of an unseen narrator.
 * The sorcerer & healer couple were given names; Michiko LOVE(ミチコ LOVE; the male sorcerer) & RYO's Wife (the female healer).
 * Mentioning of the 《Wedding Ring》 is omitted.
 * Mentioning of how Takuma got 《The Demon Lord's Ring》 from the 《Demon Lord of the Mind, Enkvaros》is omitted.
 * Takuma instantly knew he became Diablo instead of Rem and Shera saying aloud at the same time claiming to have "summoned Diablo."
 * Rem and Shera learned of Diablo's name after he talked instead of them knowing the name before they summoned him.
 * Diablo was informed that he was on Starfall Tower when Shera mentioned that she was the one who recommended that she and Rem go there instead of Diablo deducing on his own.
 * The narration informing about Summoners and Summons is omitted.
 * The part where Rem and Shera trying to command Diablo to see who summoned him was omitted.
 * The part where Shera and Rem were about to fight with their bow and Summons respectively was changed to simply arguing.
 * The location of the talk of the Enslavement Ritual and it being reflected was changed from still being in Starfall Tower to outside.
 * Diablo demonstrating his Elemental Magic to the girls was omitted and changed for the next episode to be the one when the girls find out he could use it.
 * Explanation of how Diablo use the game descriptions of the spells to invoke the magic is omitted.
 * The trio crossing through Fort Bridge Ulug to Faltra City is omitted.
 * Meeting with Boris Marcus is changed to when Diablo and Shera are delivering provisions to the Bridge of Ulug (their second day of being adventurers (episode 3)).
 * The fight with the drunken Mages and Diablo was changed to Galluk being the only aggressor.
 * Diablo defeated the 《Salamander》 with the spell 《Explosion》 instead of a physical attack.
 * Due to the other Mages not summoning their 《Spirit》 Summons of different elements, Diablo did not defeat them in one attack when trying to determine Elemental affinities.

Differences from the Manga

 * When thinking about how he "talked to girls before", the manga had two Cross Reverie players, whereas the anime only showed one.
 * Diablo's imagined cohabitation scenarios, one with Shera and another with Rem, which are both set in his world, are left out.