1. Ryu - Kan (Weaponsmith Artisan):- Go to his island in the skies just south of Yafutoman airspace (through a stone reef) and he will join you so long as you have a standing above 'Vyse the Brave'
2.Illchymis (Item Merchant Artisan):- Go to his island in the skies just north of Valua, above the skyline, go in and talk to him. Ask him to join you and he will say he is waiting for a scholar of great wisdom, leave and go back in and he will say he will join whoever knows Riselem, ave one of your guys learn it and hye will join you.
3. Domingo (Lookout):- Find him at Gordo's Bistro and he will tell you that he will join only someone who is as good as him or better at treasure hunting. Get 30 discoveries and he will join you.
4. Tiki-Tiki (Lookout) He is at the top of the village in the green place (forgotten the name, havent played in a while!) and will only join you if you find the ship with only women which should be flying around the area near the moon stone mountain.