Salazar Slytherin who was one of the four founders of hogwarts and one of the britest wizard of his age, was by far the evilest and most vicious out of the 4. He had evil plans to turn the school into a pure blood only education and not accept half bloods or muggle bloods. There is not a single witch or wizard who hasnt gone bad in slytherin. Salazars skills included and skilled in Parseltounge and legilimency. The reason that the animal for slytherin is a snake is because salazar is a paseltounge and the monster is a basilisk which is a type of snake in the chamber created by salazar.