The Will To Fight (слэш)

Severus grunted, annoyed just on principle. It wasn’t that he was being inconvenienced – not at all, really, but it still bothered him when the headmistress had Potter over. It wasn’t even him – he hated all reminders of the past, the war, the before.
All of them. His left forearm twinged and he hissed in annoyance. Potter. His arm always hurt when he thought about the brat – though he was near thirty now, he could admit without too much care. What that meant for his own age – well, he wasn’t fifty yet, and that was good enough for him.
A rap on the door had him jumping from his armchair, the hairs on his arms standing up in instinctive caution. Not fear – it wasn’t bad enough for that, but he could sense that whatever was on the other side of his door wasn’t quite right.
Wand drawn, he placed down his whiskey glass and stepped over towards the door. There was no evil or dark magic being cast – yet still, there was something out there. He cautiously opened the door – and came face to face with a familiar if terribly unwelcome smile and bright green eyes.
“Good evening, Professor. May I come in?” Potter asked, smiling.