Textbook vs Real
Textbook복수는 저의 것입니다bok-su-neun jeo-ui geos-im-ni-da
Real복수는 나의 것bok-su-neun na-ui geot
Why Koreans say it this way
Moon Dong-eun's chilling declaration. 나의 (my, casual) vs 저의 (my, humble). No copula at the end — just "revenge, my thing." The deliberate incompleteness makes it more menacing. This is literary Korean, not conversational.
From: 더 글로리 EP1