Angryverse/Piggy McCool

Piggy McCool (also known as Merchant Pig) is a pig that sometimes might be part of a scheme in order to eat the eggs, or he can be your best friend in the whole world!

(Just go with the part of him being an enemy)

True Blue?
In order to steal the eggs from The Blues, Chef Pig decided to have Piggy McCool to dress up as one of them, to act as a distraction for Chef Pig to steal the eggs!

However, The Blues found out that he was a pig the whole time and strapped him onto the slingshot and was launched from the island.

Angry Birds Epic
In Angry Birds Epic, Piggy McCool (known as Merchant Pig for some reason) has a shop where you can buy resources in and many other things. He is your "friend" (that will never happen) and also perform free rolls in his Golden Pig Machine.

You can also battle him in the Battle Arenas and can hire him for free only once per day (paying the Lucky coins for additional consecutive uses) and use him the next day for another dungeon. You can also hire Piggy McCool for free in Chronicle Cave (Once per day). However, if you had used Piggy McCool in a dungeon, you cannot use him in the Cave, or vice versa. What a shame.....

Angry Birds POP!
In the game, he appears as a guest character in a short period of time, where he is playable and assists the player in any task. His Pop is the Plunder Pop, where he can shoot a bubble that destroys some bubbles and gives the player 3 bubbles. He is a hero in this game as he is in Angry Birds Epic.