How to make pets stronger?
Pets also need EXP to gain level. Different from heroes, pets gain EXP when combined with other pets (called material pets) or when fed.
Making them stronger through pet materials
Access your pet profile and touch the "Level up" section to see all the available material. Each pet provides a certain amount of EXP, wich varies according to the especies, rarity and current level of the material.
Touch a pet material to add EXP to your active pet.
Making them stronger through food
Just select the food you want, and it will be consumed by the active pet, increasing his EXP.