Extra: Rimuru's Glamorous Life as a Teacher, Part 1

Extra: Rimuru's Glamorous Life as a Teacher, Part 1 (外伝：リムルの華麗な教師生活 その１) is the third OAD of the anime adaptation of That Time I Got Reincarnated as a Slime.

Synopsis
Rimuru, who is teaching Shizu's students as a substitute at the Kingdom of Ingrassia's Freedom Academy, takes part in an orientation in actual field combat in the school's annual outdoor training event. Transfixed by the first place prize, they accept a challenge from the Class A Teacher, Jeff. However, an enemy appears before the students...

Summary
As the Students of Class S were playing volley ball near the school, Rimuru decided they will stay at Freedom Academy for a few more days while resting under a tree with Ranga. After getting hit by the ball, Rimuru was used as the replacement for the volley ball.

At the Mansion of the Domain Lord, Count Guratol, Ulamuth was seen resting on the bed because of a disease. Gesdar informed Guratol about the situation with the thieves and provides him a letter regarding the event that is held by the Free Academy in the Kingdom of Ingrassia.

In the Academy, Rimuru regrets questioning Great Sage about the newly bought antique lamp for the table in the Academy. As Jeff walks in to the teachers room, he exchange pleasantries with Rimuru. Tiss explains the outdoor training to Rimuru and essential knowledge.

Back in Class S Rimuru discusses what equipment the Students of Class S wants for the training. After the Students of Class S decided on their weapons, Rimuru hands out a book regarding tips on surviving outdoors and returns back to Tempest.

After teleporting back to Tempest, everybody in town welcomes Rimuru back and starts planning for a feast. Then, Rimuru breaks the news about going back to the Academy after getting the equipment.

To Be Continued in Extra: Rimuru's Glamorous Life as a Teacher, Part 2...

Characters
MAIN:
 * Rimuru Tempest
 * Great Sage

BRIEF APPEARANCES/CAMEO:
 * Shizu (Mentioned)
 * Elemental of Light (Flashback)
 * Ramiris (Flashback)
 * Future Chloe (Flashback)
 * Benimaru
 * Souei
 * Souka
 * Hakurou
 * Gobta
 * Rigur
 * Geld
 * Myrd
 * Dord
 * Gabiru
 * Vesta
 * Haruna
 * Hobgoblins/Goblinas
 * High Orcs
 * Dragonewts

RETURNING CHARACTERS:
 * Kenya Misaki
 * Ryota Sekiguchi
 * Gale Gibson
 * Alice Rondo
 * Chloe Aubert
 * Ranga
 * Shuna
 * Shion
 * Rigurd
 * Kaijin
 * Kurobe
 * Garm

NEW CHARACTERS:
 * Count Guratol
 * Ulamuth Guratol
 * Gesdar
 * Jeff
 * Tiss

Locations

 * Kingdom of Ingrassia
 * Freedom Academy
 * The Town of Guratol
 * Mansion of the Domain Lord, Count Guratol
 * Jura Tempest Federation
 * Rimuru City
 * Sealed Cave

Trivia

 * This OAD is bundled with the special edition of Manga Volume 14.
 * This is an anime original episode as it does not adopt any material from the Light Novels and the Manga.
 * 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).
 * This episode, along with OAD 1 and OAD 2, premiered at a special screening event held at Tokyo's Marunouchi Piccadilly theater featuring a special talk with Miho Okasaki, Chikahiro Kobayashi, Azusa Tadokoro, and Ayaka Asai the voice actors for Rimuru, Ranga, Chloe, and Kenya respectively.