Cosmo

Cosmo is a quest in Legend of Mana.

Premise
Pearl has ventured off again without informing Elazul. Fearing that the Jewel Hunter is after her after reading a note, the Jumi Knight teams with the protagonist once more to look for clues. The note lead them to Mekiv Caverns, where the Jumi of Lapis asks are nearby Mad Mallard for informations. The duck replies that he saw an inoccent-looking lady with some other female clad in green with an orange flower in her hair. The party follows the directions given by the mallard, eventually meeting with the Lord of Jewels.

Solution
Exit your front door to your Home and talk to Elazul (he should be there). Tell him you haven’t seen Pearl and have him join you.

Enter the Mekiv Caverns. Talk to the duck and work your way through the caverns to battle the Jewel Beast.