To be able to upgrade a Pet's Apraisal rank (Genius, superior, perfect) you'll need to fuse pets.
The Pet Fusion needs a Main/Major Pet (above Genius star 2), other 4 Dispensable/Minor pets (above Genius star 1), a Fusion Stone 
and 5 gold.There are two types of Fusion Stones. The Primary Fusion Stone is for pets above Genius Star 2 and below Genius Star 3.
The Exclusive Fusion Stone is for Pets at Supreme Star 1 and above.
When you fill up all the slots you'll be given a success percentage. And when completed, if success, you'll be shown the old stats and the new ones.
In case of Failure: The 4 minor pets, the fusion stone and the gold will vanish, your Main pet remains the same.
The higher the dispensable pets' appraisal rank & level, the higher the fusion's success rate.
Note: Please be warned that within an apraisal rank there are several levels. Report to Pet Classification to know your Main pets level and how many times you need to fusion it to rank up.
| Android 13 18 | Death Knight | ChristmasFairy |
| Android 14, 15, 16 | Bug | |
| Dolphin | Pig | |
| Mushroom | Shrimp | |
| Bat | Frog | |
| Wisp | Cerebus |