I, Lucius Sabatino Salazar Malfoy, was a Slytherin. I still am; your House stays a part of you even after you leave school.
I knew that I would be a Slytherin; my father, grandfather, great-grandfather and so on and so forth have all been members of Slytherin House. We are serpents, all of us, and we are all purebloods- well, my mother was half-elf, beautiful and almost immortal, but that doesn't really count.
But I digress. I am a Slytherin, through and through. Many say that I am evil because of my House, because of my name and because of my belief in the Dark Lord.
My father was one of the first wizards to join Lord Voldemort. He was captured by Aurors during the first war and received the Dementors kiss. I only just escaped the same fate.
I also had a twin brother, Louis. He too was a Slytherin, but Father disowned him after he married a Gryffindor. She was a pureblood, but she was also a blood-traitor. I think her name was Juliet Granger.
But once again I must digress. I, as a Slytherin, have much faith in my Lord. He, finally, will purge the world of the unworthy and save our kind from extinction.
The fact that we Death Eaters are almost all Slytherins does suggest that only those with enough wisdom, enough will and enough ambition could ever have the strength to do as we do. He will conquer death. Death will never claim our race, not when the muggles are dead.
Yes, I, Lucius Malfoy, am a Slytherin, and I am proud of that fact because it is we, the evil Slytherins who will prevent the death of our race.