뭘 원하는지

what you want

→ 뭐+를
phrase Uncommon #6,449
what you want 뭘 is a shortened form of 무엇을 (“what”), and -는지 marks an embedded question, often used with verbs like “know” or “tell.”
KO: 네가 뭘 원하는지 말해 줘.
EN: Tell me what you want.

뭘 원하는지 알아요?

Do you know what you want?

— 드라큘라: 어 러브 테일 (2025)