Extra: Rimuru's Glamorous Life as a Teacher, Part 3

Extra: Rimuru's Glamorous Life as a Teacher, Part 3 (外伝：リムルの華麗な教師生活 その３) is the fifth OAD of the anime adaptation of That Time I Got Reincarnated as a Slime.

Synopsis
Rimuru and the Class S students have made it through the first exercise of the Freedom Academy's annual outdoor training event. Class S has arrived first at the destination, the mansion of Count Guratol, and now they're ready to begin the second exercise, a cave exploration... but awaiting them there are thieves who hope to kidnap the students and make a fortune returning them for ransom money. Just when it seems like Rimuru's students have fought them off thanks to the skills he taught them, they realize a monster is lurking among the thieves! This is the final installment in the brand new episode created by the original author, Fuse-sensei, just for this OAD release!

Summary
Student of Class S found themselves facing off with a spectre. As the specter, disguised as the butler, was coming out, he revealed his true nature. The bandit that was with the spectre untied his comrades and then the bandits ran for their lives after witnessing the spectre's reveal.

The students started to fight with the spectre. As the spectre started attacking with a punch, Gale, blocked it with a Rare-level shield made with the scale of Charybdis. Alice manipulated her knives to go after the spectre while Kenya fought him with his sword and shield. The spectre manages to stop the knives thrown at him and avoid Kenya's short ranged sword swings imbued with the Greater Spirit of Light's energy. The spectre then continued to explain that his powers are far more superior than the students of Class S. When the spectre got serious, he punched Kenya and Kenya got knocked back into Gale. As a result Alice, Gale, and Kenya were knocked out after getting hit towards the wall.

The spectre then showed his true form and revealed that was actually a commander-class Phantom. Ryota and Chloe proclaimed that they would be continuing to fight against the Phantom to protect the Teacher Tiss. Chloe and Ryota charged towards the Phantom and loud noise could be heard from outside the cave. Then, the battle ended with Gale's Greater Earth Spirit Beast Gnome being defeated and consequently unsummoned, trying to protect Tiss. At this point all five children were knocked out.

The Phantom, having a conversation with Tiss, explained that at this point of time, he still plans to avoid attention by the Western Holy Church. After a few exchanges, the Phantom gave Tiss an ultimatum to choose between life and death. He then pulled out the artifact called the 'Enslavement Collar' that the thieves mentioned earlier. Tiss receives the following to options:
 * 1) Refuse the offer, she dies together with the five children.
 * 2) Accept the offer, then she has to choose one among the five children that's allowed to survive wearing the Enslavement Collar as a slave of the Phantom, while the other 4 children still end up getting killed, but Tiss may leave alive.

Then, the Phantom, monologued about how his ultimate feast was to see people in anguish. Tiss picked a sword up from the floor and raised it towards the Phantom, showing that she chose to refuse the offer. Tiss thought to herself about how she had abandoned the students in Class S before. The spectre threw the Enslavement Collar to the side and intended to hurt Tiss to the point she would cry for help.

As the spectre leapt towards Tiss, she thought to herself that she wants the kids to be saved at any cost, no matter who would undertake it and incants the word for Summon. At that time seemed to have frozen and a dark figure with wings appeared behind Tiss. Tiss asked the figure who is it, but the figure refused to reveal his identity to her. The figure then asked her whether was she willing to comply with the contract given to her to save Class S students, while mentioning that that there is a debt that he needs to pay pack to Shizue. Tiss did not care what the conditions were as she bet everything on the figure to save the Class S students. The figure proceeded to warn her about agreeing to a contract with a Demon so easily being a reckless action.

After that, time resumed and the Phantom stopped his attack weary of the suddenly appeared summoning magic circle. The figure turns out to be a Demon. With both Tiss and the Phantom being unaware that the Demon was actually the Primordial Demon Noir, Noir complimented the Phantom for knowing that Noir's summon was autonomous. Despite that, the Phantom confidently said that something summoned by someone at the level of Tiss could not possibly defeat him.

Noir appeared behind the Phantom without him being able to react and mocked him. The butler was pulled out from the Phantom as Noir jabbed his hand into the Phantom's back. The Phantom could only scream in pain as soon as Noir cut of his arms while holding the Phantom's neck from behind. Tiss could only remain shocked from the gruesome scene, while Noir was enjoying cutting the Phantom's legs. The Phantom was bleeding out from his cut arms and legs and was killed by Noir closing his hand on the Phantom's neck.

The Phantom disappeared and Noir immediately demanded his payment, which was to not tell anybody of his existence. If Tiss were to break the contract, her soul would belong to Noir. Tiss asked Noir what to report back to the rest of the teachers in the Academy. Noir suggested telling them that the Greater Spirit of Light protecting Kenya defeated the Phantom. Said spirit then appeared from Kenya's body playfully saying that he had been found out. Then after taking a final meaningful look at Chloe and with Tiss still now knowing his identity, Noir disappeared without a trace. The Spirit of Light commented that "that demon from just now" seems to have softened up compared to what he knew about him.

Characters
MAIN:


 * Rimuru Tempest
 * Great Sage

BRIEF APPEARANCES/CAMEO:


 * Shizue Izawa
 * Apito (Mentioned)
 * Milim Nava

RETURNING CHARACTERS:


 * Class S
 * Kenya Misaki
 * Ryota Sekiguchi
 * Gale Gibson
 * Alice Rondo
 * Chloe Aubert
 * Tiss
 * Gesdar
 * Unnamed Commander-class Phantom
 * Noir
 * Spirit of Light
 * Count Guratol
 * Jeff
 * Ulamuth

Locations

 * Kingdom of Ingrassia
 * The Town of Guratol
 * Mansion of the Domain Lord, Court Guratol
 * Freedom Academy
 * Jura Tempest Federation (Mentioned)

Trivia

 * This OAD is bundled with the special edition of Manga Volume 16.
 * This episode is written by Fuse, the series original author.
 * This episode is set during the events of Light Novel Volume 4: Human-Monster Interaction (Manga Chapters 40-55/Anime Episodes 20-23).