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. Upon heading to the same way the Lord of Jewels told them to go, Elazul has a bad feeling about it, saying that his core has never been this clouded before. The duo nervertheless continues forward, eventually meeting Pearl and Sandra discussing about Pearl's true purpose. Elazul orders the jewel hunter to leave her friend alone, but Sandra retaliates by throwing a sharp card towards him, paralyzing him. Sandra gloats to Pearl that Elazul's core has been scratched, as the latter tries to rescue her Jumi Knight. The Lord of Jewels makes his entrance by telling Sandra to stop this, as it is pointless to hurt one another. Sandra replies that she hates the Jumi people while continuing Pearl's harrassment by asking her why she cannot shed tears. The pure girl replies by saying that no matter how sad she becomes, tears won't fall, as Jumis can't cry. Fed up with her whining, the jewel hunter reveals that Pearl is the heiress to the memories of antiquity, and that both Elazul and Pearl have lost their sparkle. This event gives Pearl enough incentive to fight, and tranforms into Lady Blackpearl. Her new appearance makes Sandra running off in fear, and the duo are now confronted by another Jewel Beast. Now that the monster is taken care of, Lady Blackpearl asks Sandra if Florina is alive, to which the jewel hunter simply replies to answer that herself, before disappearing. Elazul is then teleported back by the Lord of Jewels to the protagonist's house, where he is seen lying on his/her bed while Bud and Lisa decide on what to do for his wounds.

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.