Snape - der wahre Held

"Hang on..." Harry muttered to Ron. "There's an empty chair at the staff table...
Where's Snape?"

Professor Severus Snape was Harry's least favourite teacher. Harry also happened to be Snape's least favourite student.
Cruel, sarcastic and disliked by everybody except the students from his own house (Slytherin), Snape tought Potions.

"Maybe he's ill!" said Ron hopefully.
"Maybe he's left," said Harry, "because he missed out on the Defence Against
the Dark Arts job again!"
"Or he might have been sacked!" said Ron enthusiastically. "I mean, everyone
hates him -"
"Or mabe," said a very cold voice right behind them, "he's waiting to hear why
you two didn't arrive on the school train."

Harry spun around. There, his black robes rippling in a cold breeze, stood Severus Snape. He was a thin man with sallow skin, a hooked nose an greasy, shoulder-length black hair, and at this moment, he was smiling in a way that told Harry he and Ron were in very deep trouble.