The fourth season of Welcome to Demon School! Iruma-kun has dropped its main trailer, giving fans an electrifying first look at the Music Festival arc and the season's high-energy musical vibe, set to kick off in Japan on April 4, 2026.
Released on March 14, 2026, the trailer showcases dynamic sequences from the upcoming episodes and prominently features the new opening theme song Ichi Ni no San ("One, Two and Three") by the six-member Japanese "city soul" band Penthouse. The track delivers an infectious blend of cool sophistication and lively rhythms, perfectly mirroring the anime's signature mix of outrageous comedy, heartfelt moments, and chaotic demon-school life.
Shintaro Namioka of Penthouse commented on crafting the song for this particular chapter:
We’ve expressed the beauty of this work—which blends a comical and pop world with moments that suddenly warm your heart—through the opening theme for a chapter that intertwines the demon realm with music. I think this is the kind of track that makes you want to get up and dance somewhere between coolness and liveliness. We hope you’ll enjoy it along with the anime!
Produced by BN Pictures, the fourth season will run for 24 episodes across two consecutive cours, ensuring a full half-year broadcast window on NHK Educational starting at 6:25 p.m. JST. This extended format allows the adaptation to dive deeply into the Music Festival storyline, where demons compete in elaborate performances and showcase their unique talents in a high-stakes, music-infused school event.
A standout element teased in the trailer is the introduction of Poro-chan (also stylized as Polo-chan), a cool-yet-adorable powerhouse character poised to steal the spotlight during the Music Festival arc. Veteran voice actor Takehito Koyasu has been cast in the role, bringing his renowned charisma and versatility to the new addition.
Koyasu shared his enthusiasm for the character:
Hello there! Takehito Koyasu is joining Iruma-kun’s world! Poro-chan’s character design is just too awesome! This cool and cute powerhouse is going to shine in the Music Festival arc, so stay tuned! I love Polo-chan so much~♪
The series continues to follow human teenager Iruma Suzuki, who—after being sold to a demon by his irresponsible parents—finds himself enrolled at Babyls Demon School as the grandson of the fearsome Sullivan. Forced to hide his human identity while surrounded by eccentric demon classmates, Iruma repeatedly gets swept into absurd situations, outrageous challenges, and surprisingly touching moments of friendship and growth. The Music Festival arc promises to amplify these elements with a fresh focus on rhythm, performance, and competition within the demon realm's bizarre society.
Since its 2019 debut, Welcome to Demon School! Iruma-kun has built a dedicated following thanks to its inventive world-building, over-the-top humor, and genuine emotional beats drawn from Osamu Nishi's ongoing manga. Season 4 looks set to expand that appeal by leaning into musical spectacle while preserving the core charm that has defined the franchise.
Viewers eager to refresh their memory or catch up before the premiere can stream the first three seasons of Welcome to Demon School! Iruma-kun on Crunchyroll, which offers both subtitled and English-dubbed versions for convenient viewing.
Sources: Official website of Welcome to Demon School! Iruma-kun & Press Release
