Long before he answers to the callsign 'Undertaker,' eleven-year-old Shinei Nouzen is assigned to the Halberd squadron on the Eastern Front, an Eighty-Six conscript shunned even by his own side. Squadron captain Alice Araish treats him as a child rather than a weapon and gives him the scarf he keeps for years after, and when the unit is wiped out around him he salvages a broken Scavenger drone and names it Fido. This prequel manga covers the years that make him the Reaper.