Go back to the Iifa tree and go up the trunk once again to meet Kuja. After a chance for reorganization you can confront Kuja but he summons Mistodons for you to play with instead.

After a couple battles you can save with Mocchi who's hidden behind a root at the top. As you run down the root, you'll be attacked by more Mistodons.

Dagger will receive an Aquamarine at the end.