You can meet the tribal Guardian Trickywoo at the Dream Carnival of HKO, where he is available as one of three guardians for the Dream Carnival you may choose from. This escort-character will explain the different areas of the Dream Carnival as soon as you get close to them and will introduce a few important characters of Sanrio Land.
After you have chosen your guardian, he will always stay close to you just like a pet would. But you won't need to feed, pet or clean him. He also won't carry anything for you like some pets do and doesn't have any pet-stats. He neither will fight with/for your nor help you collect materials.
When you leave the Dream Carnival going to Sanrio Harbour the guardian will stay behind to help another newcomer.