Robin, Batman’s son and current protégé, is thrust into Feudal Japan alongside Nightwing, Red Hood, and Red Robin during an Arkham Asylum skirmish. Stranded in the past, the quartet allies with Eian’s Bat-Clan, aiding their mission to locate Batman amid his oceanic clash with Joker. A cataclysmic explosion during this battle temporarily strips Joker and Harley Quinn of their memories, though both later recover.

Two days afterward, Robin joins forces in a strategic assault alongside Batman, Eian’s warriors, and Catwoman, overwhelming the gathered villains. Their victory sees the antagonists imprisoned and the group returning to the present, where they surrender the captives to Commissioner James Gordon.

In the climactic showdown against the fused super robot Lord Joker, Robin proves instrumental by enabling the fusion of a colossal samurai monkey with a swarm of bats, birthing the entity “Batgod” to secure victory. A defining moment sees him wielding a mystical flute to command a simian army—later relinquished to Batman by Gorilla Grodd.

Robin’s arc emphasizes his adaptation to feudal combat tactics and uneasy collaboration with ancient ninja clans, navigating the era’s brutal challenges without compromising his identity.