I know, I know. I'm supposed to be finishing my other stories. My brain came up with this story and I had to write it.
Severus Snape, also known as the Bat of the Dungeons, the Potions Professor, and the Headmaster, (to name a few) watched as Hogwarts burned.
The resistance inside of the castle had grown, as it had outside the walls. Everyone had known that things were coming to a head, but no one had wanted the final battle to be on the school grounds.
The man sighed as he watched the individual battles. He saw many of his students, children that he had mocked and belittled for years, fighting for their lives and their freedom.
A yell caught his attention and he turned his attention to a fight between a 6th year Gryffindor and a Death Eater, only now there were two Death Eaters and a Slytherin 6th Year.
He would recognize that Slytherin anywhere. She was a clever, muggle-raised witch who excelled at potions and DADA. She also looked like Lily Potter, only with blue eyes instead of green.
The ginger witch was standing in front of the Gryffindor, who had been knocked off balance. Snape watched in silence as the girl skillfully redirected a spell toward a Death Eater before firing a few of her own. In seconds the Gryffindor was back on his feet, back-to-back with the Slytherin, defending their position.
The fight went on, with more Voldemort supporters showing up and surrounding the pair. Snape had an odd notion to step in and defend his Slytherin, but before he could, two powerful spells tore through the attackers and threw the rest off. Two more Slytherins had joined in the fight. One hadn't been a Slytherin for a few years, yet she wore her Slytherin house robes proudly. The other was a current 7th year and had a knack for disappearing during the past school term. Now Snape knew why.
The three Slytherins and one Gryffindor made quick progress against the Death Eaters and had soon pushed the enemy back. Ariana Night and Blaise Zabini nodded to their compatriots and left, leaving Colin Creevy and Lis Backhurst.
The two students embraced, then gave each other a quick kiss. They broke apart and set of toward the school, leaving an stunned Potions Master behind.