만 남았군

… is all that's left

→ 만
phrase Rare #31,143
… is all that's left 만 means “only,” and 남았군 expresses that something remains, often with a sense of realization or discovery. The item that remains comes before 만.
KO: 이제 숙제만 남았군.
EN: Now all that's left is the homework.

"이제 우리 집 대문만 남았군"

Now all that’s left is our front gate.

— 로렌스 애니웨이 (2012)

그럼 알려 줄 일만 남았군

Then all that's left is to let them know.

— 프린세스 브라이드 (1987)

드디어 우리만 남았군

At last, it's just the two of us.

— 저수지의 개들 (1992)

결국은 이렇게 너와 나만 남았군

In the end, it’s just you and me left.

— 프린세스 브라이드 (1987)