Slytherin

The Slytherin House, characterized primarily by greed and cunning. 
It was founded by the Wizard Salazar Slytherin. 
The common room of this house is located in the dungeons, going through a series of numerous underground corridors.
Possibly you access them through the lobby Hogwarts. 
Specifically it is located under the Black Lake, making the common room is cold, with a greenish hue as there are windows overlooking the water. 
Accessed by a highly concealed door in a stone wall, saying a required password. 
The only known is "Thoroughbred". 
The representative animal is the snake, and the element is water associated with the cunning and coldness.