Milim Confronts the Chaos Dragon
Episode 83 of That Time I Got Reincarnated as a Slime Season 4 picks up one of the franchise's most emotionally loaded threads. According to the synopsis released by Japanese entertainment site Oricon News, the episode follows Demon Lord Milim as she comes face-to-face with the Chaos Dragon, a creature she herself sealed long ago. The catch: the Chaos Dragon was once Milim's friend, and she can't go through with destroying it.
Rimuru steps in with a different plan. Rather than killing the dragon outright, he aims to protect the soul still lingering inside it. The preview images show a younger version of Milim alongside intense battle sequences, suggesting the episode will dig into her backstory while the present-day conflict plays out.
This follows directly from Episode 82, "The Master of Greed," which saw Rimuru clash with an enraged Mariabell while Yuuki entered the fight.
Season 4's Biggest Arc Yet
Season 4 launched on April 3, 2026, on Nippon Television's FRIDAY ANIME NIGHT block, and the first two cours (24 episodes) are airing back-to-back without a break. The broader arc centers on the aftermath of Tempest's National Foundation Festival: Rimuru's nation has opened diplomatic ties with the wider world and is pushing toward a "Human-Monster Coexistence Sphere." Not everyone is on board.
Granbell Rozzo, a former Hero and the eldest of the Kingdom of Siltrozzio's Five Elders, and his granddaughter Mariabell are scheming against Rimuru under the banner of protecting humanity through dominance. Meanwhile, Demon Lord Leon is making moves of his own in El Dorado. The season's introduction teases that a new "Hero" is about to awaken as these threads converge.
Eight Bit returns as the animation studio, with Tsuda Naokatsu directing and Ogawa Hitomi on series composition. The full Season 4 run is planned for five cours and 60 episodes total, making it by far the largest single-season commitment the franchise has undertaken.
About the Series
That Time I Got Reincarnated as a Slime follows Satoru Mikami, a salaryman who gets stabbed and wakes up as a slime in a fantasy world. Taking the name Rimuru Tempest, he builds a nation where humans and monsters coexist, picking up allies (and enemies) along the way. The source material started as a web novel on the Shosetsuka ni Naro platform, was adapted into a manga by Kawakami Taiki and published by Kodansha, and has crossed 56 million copies in circulation across all formats.
The anime first aired in October 2018, with Season 2 following in 2021 (split across two cours), Season 3 running April through September 2024, and a theatrical film releasing in 2022. A new theatrical anime is currently in cinemas in Japan.
Looking Ahead
Episode 83, "Milim's Friend," airs June 19, 2026 in Japan. Crunchyroll simulcasts Season 4 internationally every Friday at 7:00 a.m. PT / 10:00 a.m. ET, covering North America, Central America, South America, Europe, Africa, Oceania, the Middle East, CIS, and Southeast Asia. Amazon Prime Video carries the series in Japan.
With 24 consecutive episodes planned for the first two cours and 60 total on the horizon, Season 4 still has a long road ahead. The Milim and Chaos Dragon conflict has threaded through multiple seasons, and Episode 83 finally puts it front and center.