Tensura Season 1 Episode 4 Explained: In the Kingdom of the Dwarves
Full spoilers for That Time I Got Reincarnated as a Slime Season 1 Episode 4, "In the Kingdom of the Dwarves." If you haven't watched, stop here.
This is the fourth entry in this blog's backfill series working through That Time I Got Reincarnated as a Slime from the beginning. Episode 3 ended with Rimuru's goblin-and-wolf community freshly evolved and en route to Dwargon in search of dwarf artisans who could help build the settlement out into something more permanent. Episode 4 picks that journey up and delivers exactly what the trip promised — but not before Rimuru's introduction to dwarven civilization goes sideways almost immediately.
When and where it aired
"In the Kingdom of the Dwarves" (Japanese: "Dowāfu no Ōkoku Nite") aired October 23, 2018, the fourth week of the show's original Tokyo MX broadcast run. Per Wikipedia's episode list for the season, this installment directly follows "Battle at the Goblin Village" and picks up the journey to Dwargon that episode set in motion.
Who made it
According to Wikipedia's episode-list and season 1 pages, this episode was directed by Tokugane Tanizawa, with Taizo Yoshida handling the storyboard and Kenichirō Katsura credited as chief animation director. As with the previous two episodes, that's yet another rotation of names behind the camera — a different director, storyboard artist, and chief animation director than any prior installment, consistent with how the production spread duties across a wider team for the weekly broadcast. Eight Bit remained the studio behind the production throughout.
Arriving in Dwargon, ending up in jail
Episode 3 closed with Rimuru setting out for Dwargon alongside the goblin Gobta, and Episode 4 opens with that pair actually reaching the city. It doesn't go smoothly. Per Wikipedia's synopsis, Rimuru ends up getting into a fight with some thugs almost immediately after arriving, and the result is that he's thrown in jail for it.
That's a notably less triumphant entry into a major city than the previous episode's ending might have suggested. After three episodes of Rimuru steadily accumulating power, community, and momentum — mass-naming an entire village, brokering peace between goblins and wolves, setting out with a clear goal — the show resets him back down to street level the moment he sets foot somewhere new. A slime capable of the kind of magic that reshaped an entire settlement one episode ago still ends up in a jail cell over a street brawl, which is as much a joke about Rimuru's circumstances as it is a plot beat.
Getting out, and meeting Kaijin
Rimuru doesn't stay locked up for long. According to Wikipedia's synopsis, he's eventually set free after providing the guards with potions — a small, practical use of the kind of alchemical knowledge Rimuru has been quietly demonstrating since the very first episode, and a reminder that his usefulness in this world isn't limited to combat or naming. It's the same instinct that's carried him through the first three episodes: offer something valuable, and doors open.
That release is also where the episode's real hook shows up. Per Wikipedia's synopsis, Rimuru is introduced to Kaijin, a blacksmith, following his release from jail. Kaijin becomes the episode's second major figure after Rimuru and Gobta, and the introduction sets up the transaction that defines the rest of the episode.
Some fan-compiled episode guides describe this introduction as happening through a character named Kaidou, described as Kaijin's brother and the boss of three miners Rimuru had healed earlier in the story. That detail isn't confirmed by Wikipedia's synopsis and wasn't independently verified here, so it's worth flagging as unconfirmed rather than treating it as settled episode-4 content — the meeting with Kaijin itself is confirmed, but exactly how Rimuru gets introduced to him is not something this post can state with confidence.
The deal: magisteel for artisans
The core of the episode is a trade. Rimuru had been gathering magisteel ore during his time in the caves earlier in the story, and per Wikipedia's synopsis, he puts that ore to use here — helping Kaijin fulfill an order of longswords using the magisteel Rimuru had collected. In exchange, Kaijin agrees to help provide artisans for the goblin village, which was the entire reason Rimuru made the trip to Dwargon in the first place.
It's a clean, mutually beneficial arrangement, and it's consistent with the pattern this backfill series has tracked across the first three episodes: Rimuru's biggest wins so far haven't come from raw power alone, they've come from finding what the other side needs and offering it. The Direwolves got peace instead of extermination. The goblins got a leader instead of a conqueror. Kaijin gets help fulfilling an order he presumably couldn't finish on his own, and in return, Rimuru's fledgling community gets the craftspeople it needs to become something more than a cluster of huts in the forest.
Some fan-compiled guides go further, describing Kaijin as having been ordered to produce twenty magic swords without enough time or ore to finish them because of interference from a minister named Vesta, and describing Rimuru using his Great Sage and Predation abilities to duplicate one finished magic sword into nineteen magisteel copies. None of that is confirmed by Wikipedia's synopsis for this episode, and research done for this post suggests the Vesta conflict specifically belongs to the following episode rather than this one — so those specifics are presented here only as unverified, fan-sourced detail, not as confirmed episode-4 plot.
A toast at the elf bar, and a figure approaches
With the deal struck, the episode winds down on a celebratory note. Per Wikipedia's synopsis, Rimuru and the dwarves celebrate at an elf bar — a small, human-scale beat after the transactional business of the ore-and-swords exchange, and the kind of moment the show has made room for before, letting its characters actually enjoy a win rather than immediately rushing to the next conflict.
That celebration doesn't get to stay quiet, though. Wikipedia's synopsis ends the episode with a single line: as Rimuru and the dwarves celebrate, a figure approaches. Notably, the synopsis doesn't identify who that figure is. This post isn't going to guess at that identity beyond what's actually confirmed — doing so would mean asserting a plot detail with no source behind it, which isn't something this backfill series does.
What can be said, with appropriate hedging, is that IMDb lists the following episode's title as "Hero King, Gazel Dwargo," which at minimum suggests that Dwargon's ruler is about to become a much bigger part of the story than he's been so far. That's a secondary source rather than the primary synopsis, and it's being flagged here specifically as an inference about where the story is heading next, not a confirmed reveal about who approaches Rimuru at the bar.
How this fits the show's shape so far
Structurally, Episode 4 functions as a hinge. The first three episodes were almost entirely contained within the Jura Forest — the cave, the goblin village, the fight with the Direwolves. This episode is the first time Rimuru leaves that space entirely and steps into an actual city with its own institutions, guards, jails, and economy. That's a meaningful widening of the show's scope, and it happens through a fittingly mundane sequence of events: not a grand entrance, but a bar fight, a jail cell, and a trade negotiation.
It also continues the throughline this series has tracked since Episode 2. Rimuru's method of engaging with new places and people so far hasn't been conquest or intimidation — it's exchange. Potions for freedom. Magisteel for artisans. Even the earlier naming of Veldora and the goblin-wolf alliance fit this same pattern of giving something valuable in order to build a relationship rather than simply seizing what's wanted. Dwargon is Rimuru's first real test of whether that approach scales beyond the forest, and by the episode's end, it's working — Kaijin's cooperation secured, artisans on their way to the goblin village, and the trip that started with a jail cell ending with a toast.
What this episode confirms and doesn't
To be clear about sourcing: the broadcast date of October 23, 2018, the episode's English and Japanese titles, and the Tokugane Tanizawa, Taizo Yoshida, and Kenichirō Katsura credits are drawn from Wikipedia's episode-list and season 1 pages, presented here with ordinary confidence as Wikipedia-sourced facts that weren't independently cross-checked against a second primary source. The plot beats — the fight with thugs and the jail time that follows, Rimuru's release after providing potions to the guards, the introduction to Kaijin, the magisteel-for-longswords deal that secures artisans for the goblin village, the celebration at the elf bar, and the unidentified figure approaching at the episode's end — all come directly from Wikipedia's own synopsis and are presented with full confidence. The character Kaidou, the minister Vesta's interference, the twenty-magic-sword order, and Rimuru duplicating a magic sword using Great Sage and Predation are drawn only from fan-compiled episode guides that weren't independently fetched or verified, and are presented here as unconfirmed detail rather than settled plot — in particular, the Vesta conflict appears to belong to the next episode rather than this one. The next episode's title, "Hero King, Gazel Dwargo," is sourced to IMDb and is flagged as a secondary source used only to suggest a direction the story may be heading, not to confirm who the approaching figure is. No manga chapter or light novel volume correspondence is being asserted for this episode, and MyAnimeList's episode numbering wasn't used as a sourcing basis here.
Where to watch
That Time I Got Reincarnated as a Slime Season 1 remains available on Crunchyroll, with this episode accessible as the fourth installment of the original 2018 broadcast run.
What's next
With Kaijin's cooperation secured and artisans set to head for the goblin village, and with an unidentified figure having just approached Rimuru's celebration, the next episode looks set to bring Dwargon's ruling structure into the story more directly — IMDb's listed title for the following episode, "Hero King, Gazel Dwargo," points that way, though nothing about who that figure at the bar actually is has been confirmed yet. This backfill series will keep moving forward episode by episode from here, continuing to build the throughline toward the Season 4 material this blog has already covered.
The next episode is titled "Hero King, Gazel Dwargo" per IMDb, which suggests the mysterious figure who approaches at the elf bar and the ruler of Dwargon are about to become central to the story, though the identity hasn't been confirmed in any synopsis yet.