Subaru remembers—everyone else forgets.
The show frames this as a curse, a limitation of his Return by Death ability, but it is neither—it is a choice disguised as physics.
When Subaru tries to warn Emilia about future threats, he cannot simply speak or transfer information. Re:Zero never explains why Return by Death specifically creates amnesia in witnesses while leaving Subaru intact—because rationalizing it would expose the real argument: that consciousness cannot safely hold information a body hasn't experienced.
You cannot know trauma you have not survived.
Take the Season 1 finale. Subaru has lived through the same week dozens of times—Emilia has lived it once. When he screams the truth at her, she cannot integrate it because her neurology rejects it.
Re:Zero doesn't argue for Subaru's heroism despite his isolation—it argues that isolation is the only ethical position once you understand how fragile consciousness actually is.
Watch Season 1, Episode 18 (Emilia's response in the throne room) and then read Antonio Damasio's 'Descartes' Error' on why emotion is not separate from cognition — the book that changed how neuroscientists see consciousness between 2010-2020, the exact window when Re:Zero was being written.
The episode commentary track for Re:Zero Season 2 Episode 8 (available on some Japanese Blu-ray releases) has director Masafumi Tamaki discussing why he specifically avoided showing other characters' subjective memories of loops — a technical choice that rejects anime convention and enforces the neuroscience principle that consciousness cannot be shared across traumatic discontinuity.