Pet System
here's what I think about your pet system, there are two types of pets, one is the fighter's pet, and the second, assist's pet.
Fighter's Pet [any name desirable for the fighting pet]
fighter's pet are pets that can help the player fight their mobs in an easy way, the pet can also have an inventory, the pet is a hero, and it has skills only for itself, like critical strike, maul, self-roar etc. the pet dies when its killed in action.
concept: fighter's pet must be large creatures similar to Boar, Wolf, Bear, Kodo etc.
Assist's Pet [any name desirable for the assistant pet]
assist's pet are pets that provide the players boosting auras that can support them in battle, but the pet doesn't have an inventory [depends if you want it to be], the pet is a hero and its invulnerable, it doesn't attack, it has skills that only supports the player not its allies, like regeneration aura, critical aura, armor, etc. the pet dies when the player's class hero is killed.
concept: assist's pet must be small critters similar to chicken, skink, dog, pig etc.
you can only choose 1 type of pet depends if you want it to be full house for the player's digest.