Phantasy Star Zero Cheats :
If you enter places like Rioh Snowfields, Maraka Ruins or anywhere else, you may encounter Nests of certain rare monsters.
In Rioh Snowfield you may have a chance to find a Usanny's Nest. In Maraka Ruins you may find a Booma's Nest. For the Rappy's Nest... it can be found anywhere. No one knows until you find it.
If you find all 3 nests, you will be rewarded titles for finding them. That is all.