Snape takes the Sword of Gryffindor from its case and straps the scabbard to his waist. He Disillusions it, fully aware that it wouldn't do him any good to be seen with it as he makes his final rounds through the castle. He leaves the castle, Apparates to the Forest of Dean, and prepares to perform yet another unacknowledged job for the side of Good. He really hopes Harry can put two and two together and realize exactly what he's to use the Sword for. This trek isn't worth freezing his bollocks off otherwise.
He rounds a corner on the path and comes to a lake. Perfect. He may be sworn to protect Potter, and deep down he may not even mind, but he still can find the humor in making him swim through an ice-cold lake to retrieve the Sword. Happy fucking Christmas, Potter.
The idyllic peace of the Forest is broken by the loud snap of a twig. Before he can turn, he hears a quietly-whispered "Expelliarmus" behind him. Cursing silently to himself, he slowly turns around.
"What in Merlin's name are you doing here, Snape?"
Jugson. Why is it always Jugson…
"Do you dare to question me, Jugson?"
"Why yes, Snape, I believe I do dare. Malfoy sent me 'ere. On personal orders from our Lord 'imself. Says I can find 'arry Potter 'ere. He didn't say nothing about finding you 'ere." Jugson creeps slowly towards Snape, a malevolent glint in his eyes.
Snape sees Jugson's wand hand twitch. Without hesitation, Snape pulls the Sword from its scabbard with his right hand, thanking the gods it's still Disillusioned. Jugson's wand hand immediately goes for his wand, but Snape is faster. Knowing that a second's hesitation will result in his death, he clutches Jugson's wand hand in his left, and runs Jugson through with the Sword.
Blood gushes from Jugson's abdomen. His eyes bulge, threatening to fall out of their sockets. Jugson's breath begins barking out in harsh pants as blood begins to ooze from his mouth. Snape twists the Sword for good measure, then braces his foot on Jugson's chest as he pushes him off the blade.
Jugson's body hits the snow with a sickening thud. His blood stains the snow and tarnishes the peace of the forest. Snape quickly transfigures the corpse into a stone. He hastily casts Evanesco on the area, trying to remove all traces of Jugson's blood. He removes the Disillusionment charm from the Sword and wipes the blade in the snow and dead grass for good measure.
Snape bends down and retrieves his wand from the snow. Securing it in his sleeve, he trudges towards the lake
Yet another death to protect Harry. Yet another thankless sacrifice. Yet another stain on my soul.
Yet another "justified" death for the Greater Good.
AN: Thank you so much ladyinthecloak for suggesting I join in on the Saturday Night Drabbles fun and for beta-ing this short work for me. The prompt came from Southern_Witch_69, who prompted the following: "I want to read about a Snape who has murdered someone and feels justified about it. It could be due to jealousy or because he's protected a loved one. 500 words max. Let's see what you can do in a snapshot!" I hope this fulfills your expectations!