The man central to blocking investigators from arresting South Korea's impeached President Yoon Suk Yeol has come under the spotlight himself in the political crisis sparked by Yoon's brief declaration of martial law last month.

Hundreds of South Koreans, bundled up against freezing temperatures and snow, rallied overnight into Sunday near the residence of impeached President Yoon Suk Yeol as authorities prepared to renew their efforts to detain him over his short-lived martial law decree.