Talk to Zuriel in Atlantis.

Show Quest Info

Introduction

A pet can be a faithful lifelong companion, so long as you help it grow and improve. A good pet can save your life when you're in danger, but it takes time and effort to improve your pet's strengths. To teach your pet new skills you'll first need to buy some Pet Skill Books from Zuriel in Atlantis.

NPC Dialog

Hello, my name is Zuriel and I sell a variety of LV1 Pet Skill Books.

Quest Completion

When you own a Pet, you will find it has sealed slots, which can be unsealed by a Seal Removal Stone.
It includes a attack slot, auxiliary slot, support slot, passive slot, fortify slot and special slot. Those are used to contain respective Petskill.
If some slots are not what you want, you can reset it with a Universe Emblem. Enough Universe Emblems will allow you to reset the slots until you're satisfied.
Ok, I believe you can find more information about Petskill.