Many of the witches and wizards that are apart of the Slytherin House are interested in dark magic. Not everyone that is apart of the Slytherin House is bad, they are definitely cunning and self centered.
The Bloody Baron is the ghost of the this house, he is seen as cold to the other houses. Funny enough if asked nicely he is willing to scare other people.
Notable Members:
Tom Riddle, Horace Slughorn, Bellatrix Lestrange, Narcissa Malfoy, Andromeda Tonks, Lucius Malfoy, Severus Snape, Regulus Arcturus Black, and Dolores Umbridge