noun
second in seppuku; kaishakunin
Historical term for the person who beheads a samurai performing seppuku to end the ritual. Often translated as 'second' or 'kaishakunin'.
See also: 介錯
介錯人は切腹の際に首を斬る役目を負う。
The kaishakunin is responsible for beheading the person performing seppuku.
noun
Rare modern extension; used for someone who assists or helps, often in a supportive role. Less common than the historical sense.
彼はプロジェクトの介錯人として資料をまとめた。
He organized the materials as an assistant for the project.
Compound of 介錯 (kaishaku, 'beheading in seppuku') and 人 (nin/jin, 'person'). The reading かいしゃくにん is more common; かいしゃくじん is a variant.