After your battle with Rawiri at Mokupuni Dojo, your progress through the game will become increasingly difficult. Carlos will ask you to set a trap for Clan Belsoto and you steal their clothes, then you face the clan and Dr. Hamijo inside the Volcano.
How to beat Dr. Hamijo?
Hamijo mainly has Temtem fearing the Electric type. So don’t hesitate to use Ganki (or Gazuma) at the head of the team to face his Saipat, his Kalabyss and his Zaobian. For the rest, don’t hesitate to capture a Fire type Temtem and level it up to face the Taifu of Hamijo. There will only be one Gazuma left that you can take down with your own Gazuma or your Crystle starter (if you chose this one). Earth attacks will also be effective against Gazuma.
List of Temtem of Hamijo
Gazuma: Electric and Wind types (Level 28)
Kalabyss: Water and Toxic Types (Level 28)
Zaobian: Watch out for his Tesla Prison Electric attack / Type Digital (Level 32)
Taifu: Type Nature (Level 28)
Saipat: Type Water (Level 28)
Once Dr Hamijo is defeated, Carlos will give you the precious Crystal Skates.