Pets
 There are 2 types of pets ingame. Pick-up pets which can be upgraded into Buff Pets and Raise/Caged Pets.

Pick up/Buff pets
 Pick up pets will run around and pick up items that drop from monsters. You can customise what pets will pic up via the pet filter (press U)

You can upgrade your pick up pet to a buff pet(Some pets you obtain may already be a buff pet). Buff pets will still act as pick up pets but will havethe added benfit of the abaility to add Pet Beads to them to gain extra abilities.
You can use a Pick-Up Pet Upgrade Scroll to upgrade your pet. Once upgrade when you use your Buff pet you will see the follwing window:

You will get 2 bead slots on upgrade. You can unlock the other slots (upto 9) by using a Bead Slot Key
Once you have unlocked the slots you can use Pet Beads which are available at the Scroll shop/Blue chip shop ingame on your pet to gain extra Buffs.
Raise/Caged Pets
 Raised pets follow you around and give a bonus dependent on what pet it is.
Pets are hatched from eggs (available to buy in the scroll shop). Once you have an egg you can feed it Pet Feed (created at Pet Tamer using Questies from mobs) till it reaches 99.99% you can then take the pet to the Pet tamer to turn it into a pet.
If you wish to skip using pet feed you can buy a Egg Hatcher from the scroll shop to instantly hatch your egg!

When you pet hatches you will gain one of the following pets:
Lion Tiger Fox Rabbit Unicorn Griffin Dragon
Gives +Sta Gives +Str Gives +Int Gives +Dex Gives +HP Gives +Def   Gives +Attack  

Once you have your pet you will need to keep feeding it as raised pets have HP which will gradually decrease over time when out of your inventory. Your pet will gain exp over time when out of your inventroy.
Your pet has 5 classes everytime you get to 99.99% you can upgrade your pet at the pet tamer to the next class. When you upgrade your pet to the next class you will gain a random level for your pet based on the class your upgrading too below is the table of the classes and the max level you can get per class.

Class D Class C Class B Class A Class S
  Gives upto Level 1     Gives upto Level 3     Gives upto Level 5     Gives upto Level 7     Gives upto Level 9  

The higher the level you get the better the + bonus you will get from your pet. You can use items found in the Scroll Shop to reroll the random level you get.

There are two types of optimal raised pets:-
       *Perfet Pet- S Class pet with the class levels 1/3/5/7/9- Obtainable fully ingame.
       *Mega Pet- S Class Pet with thee class levels 9/9/9/9/9- Obtainable through Item mall or trading with players.

When you pet runs out of HP or you die your pet will lose a life, you can buy extra pet lives in the red chip shop or on item mall. If you pet dies there are revival items available for you. Your pet can have no more then 99 lives at a time.