Over the next few days, Sirius recovered his strength. He didn't risk leaving the safety of the thestral herd nor shifting back into his human form. If being The Grim had protected him from the magic of the blasting curse that Septima had hit him with, changing back into a wizard might negate it somehow. He'd just have to heal a while longer like this.
Somehow, the changes he had gone through in Azkaban were more than just the size and power of his animagus form. Smelling magic was only the beginning, there was also his ability to slip through the bars despite his larger form and seek out criminals and people committing acts of evil. He was able to add magical resistance to that now as well.
Looking back on his interaction with Snivvy, while he could smell the man's Dark Mark on his left forearm, he didn't have the same stench of evil on his soul that the other Azkaban inmates had. While the darkness that surrounded and lived in the Fortress of the Dark Lord Ekrizdis had now filled in the cracks in his soul from repetitive murders, maybe being at Hogwarts for the last twelve years had allowed Snivvy's soul the time it needed to heal. Though nothing could wipe away being a Death Eater, to begin with.
When the weekend rolled around, Sirius was nearly back to full health. As the day started, dark clouds started obscuring the sky as Hagrid came to feed the thestrals.
"Looks like yeh're almost healed. Come on over ter me hut. Me an' Fang are goin' ter watch wha' we can o' the quidditch match. Should be a good one - Gryffindor vs Hufflepuff."
Sirius hesitantly followed Hagrid through the forest but stopped at the treeline as he could see students across the grounds pouring out of the castle towards the Quidditch arena. Hagrid continued into his hut and could be heard dragging something metal inside. He came back out carrying a large metal object that took Sirius a moment to recognize as a barbeque. He took a look around to see the line of students had pretty much all entered the stadium and he pulled out a pink umbrella from his pocket and pointed it to the ground, conjuring a great leather chair for himself.
Sirius smiled in the way only a giant dog could. He had never seen the man perform magic before but had never assumed him to be a squib. Hagrid took another look around before igniting a fire in the barbeque with his umbrella and going back into his hut to bring out quite a bit of meat, with a dog following behind, staring at the meat he was carrying.
Hagrid hadn't had a dog while Sirius had been in school, the big man had always been talking about getting some magical monstrosity for a pet, but this was just a mundane dog, not even a crup. The dog spied Sirius hanging at the edge of the forest and growled at him while hiding half behind his master.
" Don' yeh worry Fang. This here's a good dog. He won' hurt yeh. Come on out, puppy. I'll cook up some meat fer the both o' yeh."
Sirius slowly walked out and laid down by the barbeque. Fang stayed behind Hagrid as he started to lay the meat on the grill. He wasn't surprised the dog was afraid of him. He was nearly twice the size of the boarhound and probably smelled like death. Though, when the meat started cooking, the other dog was too distracted by the smell to care.
They could hear when the match started and Sirius heard his favorite teacher, McGonagall, call out alongside some child, announcing the players. Sirius's ears perked straight up when they announced Harry Potter as the seeker for Gryffindor. He had known that his Godson would be playing, but now he'd get to see some of it… assuming the boy flew above the top of the stands.
"Seems like even a stray dog knows Harry Potter," Hagrid commented and he pulled two ribs off the grill. Sirius had no idea what kind of animal these were from, but they were too big to be anything non-magical. One rib was given to him and the other to Fang and they both started chewing the meat off them. It was at that moment that it started to rain as well.
Hagrid groaned and opened his umbrella while tossing it in the air over the grill. Despite its small size, it seemed to be keeping the rain off the entire area where they were sitting while they continued to listen to the game being played. Occasionally some of the players would go out over the top of the stands and they could see them dive back in. Each time that happened Hagrid cheered loudly, regardless of the team. As the game went on, the rain grew harder and heavier.
It got to the point that they could barely see the stadium from where they were sitting, but they could still hear the announcers calling the plays. Hagrid and the two dogs were still content, and dry, under Hagrid's magical umbrella eating the giant ribs. Fang had even moved closer to Sirius so they could chew on one of the bones together. That's when Sirius started feeling the unnatural chill. He lifted his head and looked towards the edge of the forest as he saw a dozen dementors fly over the trees and up into the clouds towards the Quidditch stadium. Sirius whined but was sure they wouldn't dare to go so close to the students, particularly Dumbledore.
"And Potter's seen the Snitch!" they heard the student announcer call out.
There was a sparkle of gold they could see, even through the torrential rain, shooting straight up in the air from the middle of the quidditch stadium followed by a dark shape that had to be Harry. He rose higher and higher until he disappeared into the clouds above the stadium. Sirius watched with frightful anticipation, with his worst fears confirmed as that dark shape fell from the sky moments later.
He took off with a sprint towards the stadium, but stopped as a giant white light blossomed from inside along with the booming voice of Dumbledore calling out "Arresto Momentum!"
Dumbles had caught Harry. He stood there in the freezing rain, catching his breath as a broom without a rider flew by his head. He tracked it as it went straight into the branches of the Whomping Willow and he saw the deadly tree tear it to pieces. That was probably Harry's broom. A large group of people, led by Dumbledore and Remus Lupin, ran from the stadium levitating a body. Not having anywhere to hide, Sirius just lay flat in the mud and hoped the horrible weather would hide him. While flat on the ground, he started to see the dementors in the clouds floating down towards the stadium. Moments later five patroni flew up towards them and dispersed them, as they screamed and took off in random directions. This would be a good time for Sirius to return to his cave.
When he arrived back at the cave where he had his belongings, he used his wand to dry himself off. All of the conjured and transfigured items like his bed and chair had vanished. He wanted to plan his next move but he heard The Grim growling in his mind.
When he was The Grim he was in control of the beast, but when he was Sirius, he could feel the dog in his mind pushing him to pursue his chosen path of vengeance. With his objective denied again, he needed another outlet. Luckily, as he had learned on his trip up to Hogwarts, this country had no shortage of criminals that needed to be disposed of. However, he wanted the next ones to be meaningful.
While in Azkaban, he made sure to track who came into the prison, but more importantly… who didn't. Plenty of Death Eaters got off by claiming that they had been forced to service Voldemort, either through blackmail, threats, or the Imperius curse… and somehow people fell for that. So there were plenty of people for Sirius to kill out here. He would love to kill Lucius Malfoy, but the man had far too much protection. Though some of that could be lessened. He could take away those that supported him starting with Crabbe and Goyle.
Unfortunately, both of them lived back in Southern England, down past London. He couldn't take the floo, so he was back to going on foot. He might be able to risk taking a floo to return to one of the homes abandoned by the Hogsmeade residents fleeing the dementors, but he had nowhere down south that could cut his journey short.
With his goal in mind, he gathered up some food, extra clothing he had stolen, cosmetic and disguise potions, his favorite issue of Witch Weekly, and took off into the pouring rain, heading south.
Sirius found that he was moving much faster in his canine form than he had been previously. Even taking breaks, for food and rest, he was averaging around fifty miles a day now. The Grim seemed to have more energy and its strides were longer as it was on the hunt for its next kill. Sirius felt free as he ran across the countryside. He could feel the presence of other criminals around him as he traveled, but he ignored them so he could focus on his target.
Out of the two supporters of Malfoy, Goyle was larger but his family was known more for their brutishness than their magic. Crabbe on the other hand was more wiley and most of the crimes he was 'under the imperius curse' for were related to torture through magical means. It was a bit of a tossup who he should go for first. Goyle would be more difficult for The Grim to kill, simply due to his size, but Crabbe would be unpredictable in his defense. The decision ended up being made based on who would be second. Goyle would be Goyle in any situation, however after his friend? associate? partner in crime? was killed, Crabbe would have the biggest behavior change. It would be more important to kill off the more slender of Malfoy's supporters using the element of surprise, then go after the larger one later.
The more metropolitan areas were harder to get through, for two reasons. There were more criminals in them which meant he had to push down the Grim's growling to go after them and push on. Also due to more witnesses to his movement, he needed to travel only when it was dark out. After just over two weeks, he managed to go down to the southern coast where Merton Crabbe lived with his family.
The man lived in a small manor house on a modest-sized piece of land. The property was surrounded by an eight-foot wall. The main gate had a path straight up to the small manor house lined with shaped shrubbery. There was a small fountain with a gargoyle in the center at the end of the path. Most of the wards around the property were for repelling muggles, though there were a few alarms that were easy to sniff out. Now all he had to do was wait. Sirius observed the property for a few days and witnessed a large number of human servants scurrying around the property. Trimming the hedges, tending to the horses that lived in the stables behind the house, most of them without using a wand. It was very curious.
Every evening Madam Crabbe kissed her husband and left for what she told him was to spend time with her friends; book club one night, the theater the next, or just for drinks and fun. Each night she came back smelling of a specific man and sex. How her husband didn't suspect anything was mind-boggling. The Grim didn't seem to have any desire to kill her, so the next time she was out would be the perfect time to sneak in and take care of her husband.
Sirius had been spending as much time as he could digging a hole under the wall. It would be quite a tunnel as he had to start about twenty feet from the wall on his side, near a copse of trees to disguise the entrance. When he was able to poke his nose out of the ground on the other side, he knew he could strike. That night, when Crabbe's wife left for a nighttime quidditch match, Sirius snuck onto the property.
Just inside the property was a patch of spiky bush which he took a long route around. That magical plant was a great defense against invasive animals as it would shoot small needles at creatures that got too close. Approaching the house from the rear, he found a servant's door that led to the stables and snuck into the house there. None of the servants were out and about though he was able to follow their scents from all around the house to the stairs heading down to the basement.
Sirius had a bad feeling about this.
There was no magic securing the door, so he was able to turn the knob with his mouth and creep down the stairs. He could hear music playing further down as he moved silently through the dark basement. He approached a door that was slightly ajar, seeing light on the other side, and pushed his nose through to open it just a little more.
On the other side was a small theater, with four rows of seating. On the stage was the collection of servants performing some kind of erotic ballet. Primarily women with a few men mixed in, they were all naked and dancing. Some together, some by themselves, but all with a blank look on their faces. Sitting in the front row was Merton Crabbe, conducting the dance with his wand. When Sirius had observed the servants from afar, he wasn't able to tell, but this close he could see they were definitely under the Imperius Curse.
This was probably why his wife went out every night. Maybe she didn't want to be involved in this crime, got tired of it, or just wanted someone to pay attention to him instead of her doing whatever the fuck this was. Regardless, his lapse of attention to what was behind him gave Sirius the perfect opportunity.
He crept silently down the stairs on the left side, keeping as low as possible. The dancers continued their performance for the man as he conducted two of the women to embrace in a deep kiss. As he licked his lips, Crabbe must have noticed the movement to his side and turned to look the red-eyed dog in the eyes right before it pounced on him.
Sirius managed to get one good bite into the man's throat as he was pushed away. Blood started pouring out as he staggered backward, while the music continued to lay and the dancers continued to perform. Sirius bounded over the upper seats to attack him from behind as a few weak spells were cast at him, none of them hitting. He continued to circle the man who was losing blood until he tripped and fell. The Grim took that opportunity to pounce on him and finish the job.
Crabbe wasn't finished yet. As Sirius bit back into the man's neck to finish the job, he felt the man's wand push into his side, and pain course through his body. The effect felt lessened, but after feeling it from his parents as a childhood punishment and small bits during the war, he was able to positively identify it as the Cruciatus Curse. Ironically, this spell probably killed him faster. As pain coursed through his body, the mouth of The Grim snapped shut and his body spasmed until it tore the man's head clean off. At that last moment, Sirius swore he saw the man's soul leave his body and dissipate into the air.
As he lay on the ground recovering, he heard the dancers fall to the ground in a heap. As he started to regain control of his limbs they began to scream and cry. When he was finally able to lift his head again, the group was all lying about the stage, some of them holding each other as they wept and cried out. When they spotted the black dog standing up again, their tears stopped and they looked at the fearsome predator that had just slaughtered the man controlling them and wondered if they would be next.
In hopes of assuaging their fears, Sirius picked up Crabbe's head in his mouth and flung it onto the stage where they were, the lifeless eyes rolling to face them. He gave a loud bark and started to lead them out of the room. They all gathered their clothes that were in the next room and he guided them out to the hole he dug out of the property, not knowing if it would be safe to leave through the front. Stone gargoyles in magical households would often attack people the tunnel had already been tested going in. Once they were outside the walls, they took off on their own, though he didn't know where they would go. Hopefully, they would go find Aurors.
