Arifureta - Episode 01

"The Monster of the Abyss" (奈落の底の化け物) is the first episode of the anime adaptation. It aired in Japan on July 8, 2019.

It was pre-screened along with the second episode during the "Arifureta: Strongest Week Event" on July 7, 2019.

Synopsis
After he and his entire class are summoned to another world, Hajime Nagumo finds himself extremely underpowered and at the mercy of the Labyrinth.

Summary
The episode begins with Hajime Nagumo being thrown into the abyss of the Great Orcus Labyrinth. At the bottom, he quickly finds monsters stronger than he's ever seen. One of them, a bear like monstrosity, tears off his arm and eats it right in front of him. Hajime escapes by transmuting his way deep into the ground. By a stroke of luck, he finds a Divinity Stone that creates a constant, nigh-unlimited pool of Ambrosia, allowing him to staunch the bleeding of his now-missing arm.

In a few flashbacks, it is revealed that Hajime was pushed into the abyss by one of his classmates after trying to save Kaori from a Behemoth. Hajime is stuck in the Abyss, and starts to break due to intense hunger. He eventually loses reason, and begins to hunt the extremely strong wolves by using traps. Upon eating one, the cells of the monster change his DNA, and only the constant healing from the Ambrosia saves him. His body transforms, becoming much stronger due to the constant healing of his muscles that keep getting torn apart from the symbiosis of his DNA and the monster's.

After his transformation, he uses his Transmutation skill to create powerful weaponry through trial-and-error, eventually creating his first pistol: Donner. He uses it to hunt the rabbit and bear predators before looking for a way further into the abyss.

Characters
Characters in italics debuted here.
 * Hajime Nagumo
 * Yue
 * Meld Loggins (flashback)
 * Kouki Amanogawa (flashback)
 * Ryutarou Sakagami (flashback)
 * Yuka Sonobe (flashback)
 * Eri Nakamura (flashback)
 * Kaori Shirasaki (flashback)
 * Shizuku Yaegashi (flashback)
 * Daisuke Hiyama (flashback)
 * Suzu Taniguchi (flashback)
 * Nana Miyazaki (flashback)
 * Taeko Sugawara (flashback)
 * Atsushi Tamai (flashback)
 * Kousuke Endou (flashback)
 * Other Characters (flashback)

Locations

 * Great Orcus Labyrinth
 * Heiligh Kingdom (flashback)
 * Horaud Town (flashback)

Types of Monsters

 * Traum Soldiers
 * Behemoth
 * Twin-tailed Wolves
 * Kickmaster Rabbit
 * Claw Bear

Differences

 * In the LN, it is shown how the entire class is transferred to Tortus as well as how bad Hajime is treated by his classmates for his otaku habits and later his lack of any sort of combat ability. While in the Anime, the entire transfer scene is completely skipped over, while Hajime's abuse is briefly touched upon via flashbacks.
 * Hajime killing a monster in the first floor of the Labyrinth is omitted in the Anime.
 * In the LN, the creature that Hajime and others fight in the 20th floor of the Labyrinth is a gorilla-like monster that can camouflage itself. While in the Anime, is a humanoid lizard that is covered in fur.
 * In the LN, Kouki uses "Celestial Flash" on the Monster on the 20th floor, and Meld scolds him for using a powerful spell in a confined space.
 * In the LN, Hajime jumps on top of the behemoth in an attempt to further slow it down by transmuting the bridge around its entire body.
 * In the LN, Hajime dries off his clothes using fire magic after landing in the abyss.
 * In the LN, Hajime doesn't know of the names of the "Divinity Stone" and "Ambrosia" until after he meets Yue. While in the Anime, he first reads about them while he is studying in the Heiligh Kingdom's library.
 * In the LN, the meeting between Kaori and Hajime takes place at an inn run at "Horaud Town" where the Labyrinth is located and happens the previous night before the incident occurs. While in the Anime, it takes place in Hajime's room in the Royal Palace and occurs six days before the training at the Labyrinth takes place.
 * Hajime's meeting with Kaori in his room is longer in the LN.
 * In the LN, it is not mentioned if Hajime took the fur of the Claw Bear after defeating it.