KYOTO—Shinji Aoba, perpetrator of the worst postwar mass murder in Japan, was sentenced to death on Jan. 25 for killing 36 people in an arson attack at a Kyoto Animation Co. studio in 2019.

Shinji Aoba, 46, was sentenced to death in January 2024 over the 2019 blaze at the studios of Kyoto Animation – Japan’s deadliest crime in decades. But his defence team appealed the ruling ...