Grandpa Sensei from Neo Sushi will eventually ask you to collect 6 Dragon Orbs that are scattered trought Neo Sushi Island. And this part is quite funny because of the DBZ reference You can find them:

  1. Defeating Grandpa Sensei in Neo Sushi City
  2. Defeating the Tentacles in the school in Neo Sushi City
  3. In the well north of the park, after battling the Amazing Bullman in Old Neo Sushi City
  4. Defeating the Desert Arena to the east (right answers: 1.Monster, 2.MacGuffin 3.St Moriaz 4.Doom&Destiny)
  5. Defeating the Boss in the Hangar, in the waterfall north of Desert Arena
  6. Returning to R&D facility after talking to Master before getting into the air ship and find orb in the chest.

Note: R&D orb is still accessible later in game. But if it seems like you've completed all quests and you're still missing an orb, like I was, go back to the classroom where you fought the tentacle monsters and look for the small orange ball on the ground for the last orb. I fought it not realizing it was part of the quest and it didn't notify me or go into my inventory as it did with other fights.

After all return to Grandpa Sensei.