[Extract from 'Harry Potter and the Deathly Hallows']
"Take...it...Take...it..."
Something more than blood was leaking from Snape. Silvery blue, neither gas nor liquid, it gushed from his mouth and his ears and his eyes, and Harry knew what it was, but did not know what to do-
A flask, conjured from thin air, was thrust into his shaking hand by Hermione. Harry lifted the silvery substance into it with his wand. When the flask was full to the brim and Snape looked as though there was no blood left in him, his grip on Harry's robes slackened. "Look...at...me..." he whispered.
The green eyes found the black, but after a second, something in the depths of the dark pair seemed to vanish, leaving them fixed, blank, and empty. The hand holding Harry thudded to the floor, and Snape moved no more.
[End of Extract]
Severus had lost consciousness; one could expect nothing short of that after being bitten by a venomous and powerfully magical snake. But as he gathered consciousness, he saw, through partially open eyelids, that Potter, Weasley and Granger had left. Surely they would have had the brains (or atleast Granger would have had) to examine him once, to make sure he was dead? But no, Potter, the hot-headed idiot, had assumed on his own that his Professor was dead.
Most people could have been prepared for this kind of an event. Attacked by the Lord they served? But Severus did not fall into the category of "most people".
Mustering all the energy he had, he raised his hand, and, slowly, pulled out a small vial containing a bright blue potion. He had always been carrying this since the Dark Lord had gained control of Hogwarts; Severus couldn't put it past the DA to poison his food. But he was lucky that this potion was just powerful enough to expel Nagini's venom – or so he hoped.
Very slowly, careful as to not spill even a drop, Severus applied the potion to his bleeding neck. It was numb now; he was sure that if he had waited any longer, he would have died.
But the effect of the potion was, in contrast, wonderfully fast. The bleeding stopped; the feeling returned. And slowly, a liquid dirty brown in color started leaking out of his neck. The snake's venom.
Severus had acted fast enough so as to save his life.
Two hours later, Severus had gained enough of his strength to walk. The fighters of Hogwarts had gathered near the stairs leading to the Entrance Hall. Severus, who himself was Disillusioned, could see a lot of Death Eaters, apparently victorious, who were filing in front of the defenders of the castle; it seemed that Potter had done what he had to do.
In spite of himself, Severus felt a rush of affection for the boy. It would not have been easy for him; after so many years, when he had struggled and fought to stay alive, it would not have been easy to walk to his own death without raising his wand.
Voldemort was shouting; he seemed to be telling the Hogwartians a story that was most likely false. Potter would not have died running away, even Severus thought so himself.
But the foolish Longbottom had charged at Voldemort. In a second, he was Disarmed and Full Body- Binded. And now Voldemort put the Sorting Hat on his head, and set it aflame. Even as Severus raised his wand, ready to act, reinforcements were heard on the castle gates; Hagrid's Hippogriff and Thestrals were attacking Voldemort's giants, even as Hagrid's brother (Severus couldn't help but smile a little) punched them; the centaurs charged at the Death Eaters from the edge of the Forest; and Longbottom sliced the snake's head.
But before that, Severus saw something that shocked him into stillness for a solid minute. Potter had jumped from the ground and placed his Invisibility Cloak over himself. At first, Severus could not have believed it possible that he had survived the Killing Curse again, but then realized that Albus would have personally ensured that his plan would prevent the boy dying at any cost. Severus smiled richly.
Severus was furious and gleeful at the same time. Longbottom had avenged him (Snape) but Severus would have preferred if he would have done it himself.
House-elves, the tiny little creatures, came out of the kitchens and stabbed the Death Eaters; soon, the Death Eaters were scattering, because they were dreadfully outnumbered.
As Severus entered the Great Hall, he saw a Battle going on inside. He saw members of the Order flooring the remaining Death Eaters due to sheer numbers; everywhere he saw, there were Death Eaters jinxed, stabbed, hit by arrows, knocked out or simply stampeded on.
Slowly, there were only two duels left in the Hall, as every other Death Eater was either dead, injured or escaping: Bellatrix, that stupid woman obsessed with both murder and Voldemort (which actually are strongly related) was battling three at once – Granger, Weasley and Lovegood. The three girls were battling as well as they could, and no one but Voldemort and Bellatrix could have held their own against the trio. On the other side of the Hall, Voldemort also dueled three at once, but he dueled three of the most powerful wizards alive – McGonagall, Slughorn and Shacklebolt. He was dueling with a kind of fury Severus had never seen in him; Severus would have thought that he was mourning his familiar if Voldemort would have enough human left in him to do things like mourning.
As Severus saw, Weasley was almost hit by Bellatrix's Killing Curse, and Molly Weasley, of all people, pushed aside the three girls and started dueling Bellatrix. She stood no chance, Severus thought, but that was because he had never seen her duel.
Molly slashed and twirled her wand in a manner that made Bellatrix snarl; she was proving that she was the sister of the heroes Gideon and Fabian Prewett. To Severus' amazement, Bellatrix started backing off slowly, a feat even Aurors could not have achieved. And before his very eyes, Bellatrix was killed by the most unexpected person: Molly Weasley. There were so many other wizards who would have wanted the chance though. And Neville Longbottom had been Severus' guess.
What? Severus reprimanded himself for thinking that a teenager like Longbottom could have defeated Bellatrix single-handedly. But then his attention snapped back to the last duel.
Voldemort blasted his three opponents out of the way, and started on Molly. But even as Severus raised his wand to cast a shield charm, Potter had appeared out of nowhere and done it for him.
The boy and Voldemort circled each other for long, Potter talking as if he knew some secrets Voldemort didn't. And sure enough, he did know them, Severus thought, as he used Legilimency on him. Oh my God, the boy sure knew things!
And then the conversation turned to Snape himself.
[Extract from 'Harry Potter and the Deathly Hallows']
"Severus Snape wasn't yours," said Harry. "Snape was Dumbledore's.
Dumbledore's from the moment you starting hunting down my mother. And you never
realized it, because of the thing you can't understand. You never saw Snape cast a
Patronus, did you, Riddle?"
Voldemort did not answer. They continued to circle each other like wolves about
to tear each other apart.
"Snape's Patronus was a doe," said Harry, "the same as my mother's, because he
loved her for nearly all of his life, from the time when they were children. You should
have realized," he said as he saw Voldemort's nostrils flare, "he asked you to spare her
life, didn't he?"
"He desired her, that was all," sneered Voldemort, "but when she had gone, he
agreed that there were other women, and of purer blood, worthier of him - "
"Of course he told you that," said Harry, "but he was Dumbledore's spy from the
moment you threatened her, and he's been working against you ever since! Dumbledore
was already dying when Snape finished him!"
"It matters not!" shrieked Voldemort, who had followed every word with rapt
attention, but now let out a cackle of mad laughter. "It matters not whether Snape was
mine or Dumbledore's, or what petty obstacles they tried to put in my path! I crushed
them as I crushed your mother, Snape's supposed great love! Oh, but it all makes sense,
Potter, and in ways that you do not understand!
"Dumbledore was trying to keep the Elder Wand from me! He intended that
Snape should be the true master of the wand! But I got there ahead of you, little boy - I
reached the wand before you could get your hands on it, I understood the truth before you
caught up. I killed Severus Snape three hours ago, and the Elder Wand, the Deathstick, the Wand of Destiny is truly mine! Dumbledore's last plan went wrong, Harry Potter!"
[End of Extract]
'Oh you did, did you?' Severus shouted as he lifted the Charm off himself.
It was a shock for everyone, alright. After hearing the truth about Snape, the Hogwartians had been sad about how they had treated him; after seeing him die, Harry was sorry for him; and Voldemort was happy after killing him. But everyone was shocked.
The Hogwartians and Harry cheered for a moment, but stopped the moment they saw the look on Voldemort's face. It was murderous.
'YOU! You're alive! That's why the wand won't work for me!' He screamed.
'No. The true master of the wand was Draco Malfoy, because he Disarmed Dumbledore before I killed him,' Severus said.
'And I Disarmed him that night in Malfoy Manor!' Potter said. Realization dawned in all three of our faces. After all, Potter had ended up with the Elder Wand. That's why he wasn't killed. Or maybe that's one of the reasons.
Instantly, Voldemort's face was lit with a maniacal smile. 'Today, here and now, I'll kill you both, and let's see what match you are for me!'
As he raised his wand on Harry, Severus pushed Harry aside. Now he was finally facing what he had dreamt for; a chance of dueling Voldemort, to show him what Severus was worth.
'I'll show you what I can do now. You'll regret that you ever hunted Lily Evans,' Severus said quietly. Suddenly, the Great Hall was lit by a flash of fire. Fawkes the phoenix appeared on one of the demolished tables, and shouted, in Albus' voice, 'Thank you Severus! Thank you for all you did! Go on, you show him what you are!' And then it vanished again.
That was a weird message, everyone thought. After all, a Headmaster was hardly expected to speak in such a childish manner.
And then, flashes of light lit the Hall, as Severus and Voldemort sent spell after spell of deadly power at each other. Everyone who had survived the Battle was looking on, and McGonagall and Shacklebolt and Slughorn had awakened due to Albus' voice too.
Bang. Flash. Whoosh. Flash. Bang. Smat. The Great Hall was shocked to a standstill as Severus, the unfair Potions Master, dueled the most evil and powerful Dark Wizard ever. There was no doubt that this was a fantastic fight.
Severus was dueling amazingly, and Voldemort was at his peak due to anger. Everyone in the Hall ducked when suddenly Voldemort's spells started bouncing off Severus', and blasting the walls.
To the duelers, there was nobody except them. They dueled with a motive each; Severus' being his revenge for Lily, and Voldemort's being just murder.
Slowly, when he realized that mere spells would not harm Severus, Voldemort turned to Transfiguration. He Conjured huge flames, that at once charged at Severus. But three swipes of his wand, and the flames that were attacking Severus had turned to their Conjurer. Taken off guard, Voldemort barely Vanished the flames. By then, Severus had Conjured two swords and enchanted them to hack at Voldemort. As Voldemort struggled to subdue them, Severus was able to aim three spells at him.
Slowly, Voldemort's skin developed welts. Sectumsempra was the spell that Severus had decided on long, long ago to be the one to avenge Lily.
Voldemort fell to the floor. As a last attempt, he aimed a curse at Potter, who shouted, 'Expelliarmus!'.
The curse rebounded. Voldemort had been killed by his own curse. And Severus had become everyone's hero, including Potter. This was the dawn to a new era.