Yang (the geek in glasses): after you beat Kyza (robot) go back to
robot beach and you will hear his geeky voice telling you to find
him (as it does on all ninja guardians) look for kyzas fist (by the
shore of the beach) yang will be there, pay him coinage and he will
give you 2 tests (like all ninja guardians)
Aria (the fatty) on the ship with the ramp (warning: tests get
harder with each guardian)
Twikki (the leafy coward guy): on the stump near the level sly ninja
Zarola (the hot babe): right outside the moon teleporter (or the
floating moon rock thingy