Also known as: ゼロカラササゲルイセカイセイカツ, ササゲル
A Re:Zero Kara Hajimeru Isekai Seikatsu side story published on April Fools of 2026, commonly known as Sasageru or Petra IF.
Diverges from canon during arc 9 of the main story.
Takes place 400 years in the future, after Natsuki Subaru is released from a seal.