Rimuru's Demon Lord Form Headlines the New Roster
The second Kotodaman x TenSura collaboration brings seven new six-star characters to the game's gacha summon pool, all voiced by their original anime cast. The headliner is Rimuru in his Octagram Demon Lord form (voiced by Miho Okasaki), joined by Veldora (Tomoaki Maeno), Shuna (Ayaka Senbongi), Shion (M·A·O), Milim in her Dragon Equipment form (Rina Hidaka), a Ramiris and Beretta duo unit (An Haruno and Ayako Kawasumi), and Luminous (Lynn).
For fans who want Diablo, MIXI is selling a paid "Diablo (Primordial Demon) Pack" in the app store. Diablo (voiced by Takahiro Sakurai) comes with a leader bonus that grants maximum reward drops on most collab quests — a significant farming advantage during the event window.
Three more characters appear as quest-reward bosses: Hinata (Manami Numakura), Clayman (Takehito Koyasu), and Mariabell (Inori Minase). That's a total of 11 TenSura characters in one event, covering allies and antagonists alike.
Round 1 Revival and Free Summon Bonuses
MIXI isn't leaving first-collab fans behind. The original TenSura collaboration summon pool returns alongside the new one, and players can earn up to 100 free summon pulls through login bonuses. Five 10-pull tickets are handed out on first login during the event period, and one additional 10-pull ticket can be claimed daily from May 26 through June 15.
That's a generous on-ramp for players who missed the first wave or want to fill out their TenSura roster before tackling the new collab quests.
X Campaign and Official Livestream
To mark the collab launch, MIXI is running an X (Twitter) campaign from May 22 through May 24. Reposting the official campaign post enters players for a chance to win ¥5,000 (approximately $33) in digital gift credit, while posting with the hashtag #コトダマン転スラコラボ enters them for a collab character set. The full event details will premiere during the GOD Station official livestream on May 24 at 8:00 PM JST.
For those unfamiliar, Kotodaman is a Japan-exclusive co-op mobile RPG by MIXI where players combine letter-spirit characters to form Japanese words and deal damage. It's built around Japanese vocabulary, so it hasn't been localized for international markets — but its anime collaborations regularly feature full voice cast reprising their roles, making it a notable tie-in for Japanese-speaking fans.
Looking Ahead
The collab runs from May 25 at 4:00 PM JST through June 15 at 3:59 PM JST. The timing aligns with That Time I Got Reincarnated as a Slime's fourth TV season, which premiered on April 3, 2026, and is currently streaming on Crunchyroll with subtitles and an English dub across most international territories. Season 4 is planned as a five-cour run produced by Eight Bit, with the first two cours airing back-to-back through spring and summer 2026.
The TenSura franchise's combined light novel, manga, and spinoff sales have surpassed 45 million copies. The source manga by Taiki Kawakami (based on Fuse's web novel) continues serialization in Kodansha's Monthly Shonen Sirius.
Kotodaman itself is not available outside Japan, so international fans will need a Japanese app store account to participate. No English-language version of the game has been announced.