Who warns Odysseus he will face three monster?

Odysseus is warned about the three monsters—Scylla, Charybdis, and the Sirens—by the sorceress Circe. She provides him with crucial advice on how to navigate the dangers he will encounter on his journey home. Circe's guidance helps him prepare for the challenges ahead, particularly the peril posed by Scylla and Charybdis, two formidable sea creatures.