They were on the train still, peacefully enjoying Harry's enormous purchase of candy. After a time, Hermione glanced over at Harry.
"Did you really vanquish Lord Voldemort? Because if you can kill people like that, that's kind of scary." She said this very fast. "I was reading about you in some books and apparently you destroyed half the house at the same time, but you were only a baby so you shouldn't have been able to do that. How did you do it?"
"I was only a baby, Hermione," Harry pointed out. "How would I know?"
Ron, meanwhile, was vigorously shaking his head. "You shouldn't say his name, Hermione."
Hermione frowned at him. "Whyever not?"
Harry was also curious to know, and turned to Ron questioningly.
The redhead sighed. "Well, firstly, it causes a lot of people a lot of pain when you say it, so you shouldn't get into the habit. My mum lost both of her brothers, my dad lost his sister and they both lost quite a few friends; just about everybody above the age of twenty has lost friends or family to You-Know-Who, and my mum still cries whenever anybody says his name. Also, during the war, You-Know-Who set up this system to track anybody who said his name, so anybody who did say it got killed; most adults still avoid it, just in case. And then… well, there's a third reason, but it's rather silly."
Hermione nudged him. "Oh, go on. Tell us."
"Well, there's this wizarding fairytale about these three brothers who tricked Death, so Death hunted them down in revenge. They had tricked him out of three magical items; a wand, a stone and an invisibility cloak. The first brother, with the wand, went around duelling anybody he didn't like, and because he caused so much death, and wished it upon his enemies, Death found him and claimed him. The second brother, with the stone, used it to speak to his dead relatives and dead friends, and because he spent so much time talking about death, he was found and claimed too. The third brother, on the other hand, used the invisibility cloak to hide, and he spent all his time celebrating life. Because he never spoke of death, Death never found him until he was ready to die."
Harry stared at Ron. "Right. What's that got to do with anything?"
"Just like the story of Red Riding Hood is supposed to warn children about werewolves and shape-shifters, the story of the three brothers is supposed to teach people about fear and belief. Death had so much power over the eldest brothers because they knew him and spoke of him all the time, so when he tracked them they thought they could best him. If we went around calling You-Know-Who Billy Bob or something all the time, we'd stop fearing him."
Hermione frowned. "But shouldn't we stop fearing him? He's dead, after all," she objected.
"It takes quite a bit of work to keep something dead, Hermione," he told her darkly. "Necromancy and Blood Magic can bring back just about anything, and there's still Death Eaters around who would be quite happy to see You-Know-Who back. Saying his name brings him closer to the living world and makes it easier for some Dark wizard to bring him back."
The three considered this gravely for a while, sitting in the silent compartment thinking dark thoughts.
It might well have remained that way until they reached Hogwarts, but Ron shook himself out of it. "Cauldron Cake?" he suggested, offering one to Hermione with a grin.