Disclaimer: I own nothing except for my own imagination.
The Slytherins are known to be cunning and ambitious, yes. We are the sly and tricky lot, for the most part. The untrusted few, we are.
So why am I here?
Are you so dense as to propose that question, too? Or have I pulled the wool over your eyes as well? I wouldn't be surprised; my guise has worked for six years running, and it's bound to work for the rest of my life. Or, at least, up until the last few moments of it.
For you see, if I give up my disguise, I will die. The Slytherin House is ruthless. If I am found out for what I truly am, I will be seen as a threat. Someone smart enough to pull a double act is a threat, always; but here, if your ruse is revealed, you become Flobberworm fodder. Easy as pie.
Day after day, I walk around like the perfect crony. I play my part well, perhaps too well. The whole school, I believe, has been fooled by my seemingly harmless self. They believe my only strength is my strength---physical strength, that is. They make the mistake of underestimating my mental prowess.
Oops.
The only one who perhaps knows my secret is the Sorting Hat. It knew where I was to go within only a few seconds. I had already been playing the part for a few years, thanks to a boy whom I loathe more than any other.
Even Harry Potter.
Contrary to what everyone believes (as I stated before), I am not stupid. I know Harry Potter will win this fight. He is Light, and Voldemort is Dark. Yes, I am a Slytherin and I say his name here, in private. Perhaps it will help me gain your respect. In any case, Potter knows how to fight. He's not inept. He, or someone else on the Light side, will find a way to triumph. When they do, I will smile. I hope I live to see that day.
I am not stupid or bumbling. My mind is not a miring pit of sludge. I realize that the part I play is dangerous. It is likely that I will die before the climax of this play that is my life. I am not a major player, merely a pawn. As everyone knows, one of the most basic rules of chess is to send out the pawns first. They are expendable, and thusly so am I.
When will my double act end? I do not know. Not when Voldemort is defeated, surely. Won't it seem suspicious if, all of a sudden, I start acting like my true self? Colleagues who know me would uncover my ruse and murder me, of course. It would all have been for naught.
So, I am trapped here, within this mask of duplicity. I am resigned to my lie of a life. There is no escape.
"Crabbe, stop feeding your face and pay attention!" comes the whiny voice of Draco Malfoy. It is he whom I loathe and despise, the taskmaster to whom I must serve. My loyalties must always be seen to him and him alone.
Or, perhaps, to food. I like food, but gorging myself on it has become a practice I also loathe. Yet another reason to hate the Malfoy heir.
As I turn to him, my mouth somewhat open, I am smiling inside. Nobody knows my true worth, and nobody ever will. When I leave this world, nobody will care. I will just have been another pawn, carelessly thrust into battle. A sacrifice for some greater cause.
I smile inside because I know I have the ability of the queen. After all, when a pawn reaches the other side of the chessboard, it can become any piece it wishes to be.
Except a king.
Pawns like me cannot escape from their destiny. Their humble beginnings limit them, if only slightly. They cannot gain total control, total power. But why be a king? He is the target of the enemy, the ultimate goal. Who would want me? It is better, thus, to be a rook. Hidden easily in the corners, they await their moment in the late game where they can reveal themselves and take control at last.
Within my last moments, I want to laugh. I want to laugh at the world, who will never realize my full potential. They shall never know who Vincent Crabbe really was. He shall be just another name, lost in memories and glossed over for all eternity.
My lesson to you is this: Look deeper into everything. Take some time to ponder. You never know what diamonds lay hidden in the rough.