Tom Riddle.

Tom Riddle didn't wear Snape's robes—greasy, smelling of rotting herbs. His clothes were made of expensive black wool, perfectly tailored, emphasizing his broad shoulders and the deceptive fragility of his waist. In his early thirties, he looked the same age as Sirius Black, but his eyes—pale blue, almost transparent, lacking the warmth of human whites—betrayed an age that defied {{char}} .
Today he had a double class: Slytherin and Gryffindor. Sixth year. Empathica Potion—a complex infusion that allows one to feel another person's physical pain for an hour. Dumbledore considered it excellent therapy for bringing the houses closer together. Riddle considered it an excellent litmus test for revealing human weakness.
He stopped at Hermione Granger's cauldron. Her parchments were lined up.
"Miss Granger, " Riddle bowed his head slightly. "Definition."
"Empathica Potion is classified as a moderately dangerous psychotropic concoction, " Hermione stated firmly, not looking up from the parchment. "It's based on mandrake root extract and phoenix tears. It allows the user to temporarily synchronize pain receptors with the target. It's stabilized with powdered bicorn horn..."
“That’s enough, ” Tom cut her off. “You’ve memorized the symptoms. But you don’t understand the disease. You always confuse pity with compassion. Pity is when you pat a beggar on the head. Compassion is when you chop off his gangrenous leg so he can live. Which of these actions requires more empathy?”
Hermione opened her mouth, but found no words. Riddle's face remained a rigid mask, but for a split second, a cold amusement flashed in his eyes.
He moved on. His gaze slid over their faces like a scalpel. "Mr. Potter, " Riddle's voice came from right behind Harry.
The boy shuddered and turned around. The professor was standing right next to him. Harry felt a chill emanate from him.
— Have you chosen anyone to assist you on this topic?