Spells were flying left and right. Harry and his team were on their last breath, fighting out for their lives. Thankfully, Sirius, Moody, and others came in to help, but even with them, the situation was dire. He and Neville were trying to get out, but then Dumbledore appeared. And he thought that here it is, they are saved.
But then he saw spell hit Black and his world came to a stop. But then slowly it came back to a crawl, and he started falling towards the arc behind him.
"Accio doggo"
And the already falling body was tossed back in the opposite direction towards the person who cast the summoning charm.
Second, later, the mysterious man caught Sirius by his coat.
"Expecto Ignis Daemonium"
"Silencio Locus"
2 spells rocked space in which fight was taking place. First calling a terrifying creature of pure fire into our world and second enforcing silence upon the territory.
As soon as charms came in their full force, silence overcame the location, and the man thrown Sirius towards another member of the good guys.
But a sense of wrongness was growing stronger with every second. Humans, creatures accustomed to always hearing something, suddenly appeared in the location where space itself lost meaning of sound. People couldn't even hear their heartbeats.
Finally, the mysterious man who up until now, had his head covered by the long and wide hood connected to a very big coat covering his whole body, raised hands to show his face.
Surprise and recognition bloomed on the faces of those who knew that person. But the person in question, Magnus didn't care. He simply waved his hand, letting demon on the rampage, while personally slowly moved towards the arc.
He never looked at others even once. He was solely focused on the veil and energy covering this artifact.
Others wanted to help, to scream, to speak, but couldn't. Demon mercilessly was commencing a massacre among the death-eaters, who couldn't cast any spells. However, the inability to cast spells didn't affect truly powerful wizards, so they tried to escape. That included Bellatrix.
But as soon as she escaped the room, Magnus looked in her direction and, after a brief second of considering, followed.
Demon looking at how his master was leaving and how prey was running out started dissipating in the air, leaving only dust behind.
When Magnus left, Silencio moved with him. So, wizards could finally speak. That was a perfect chance for death-eaters to retaliate, but unfortunately for them, Dumbledore had more experience. They ended up stunned before they could even raise their wands.
People here collected themselves and the first thing Harry did was checking on Sirius.
However, when he learned that his godfather was perfectly fine, he as well as everyone else, capable of moving, ran after Magnus.
They expected to hear fighting sounds or at least some debris left after the fight, but they found nothing of such. On the opposite, they became spectators of a silent scene, where Bellatrix Lestrange was held by the throat, hanging in the air soundlessly gasping for air.
Unexpectedly, the Dark Lord himself appeared in the middle of the hall.
Magnus slowly moved the hand with Bella in it to the right to see the new visitor.
Voldemort noticing the spell put on the territory was able to quickly understand the situation and chantlessly fired spell towards Magnus. But boy's reaction was surprising, he only smiled and slapped spell away with his free hand.
Then Magnus, clenched his right hand, pushing his thumb up and in, thus breaking Bellatrix's neck and let her already dead body drop on the floor. What made the scene more terrifying is the absence of any sound, because the brain was screaming how uncanny this situation was.
Voldemort has frozen with his wand ready, while Magnus stood relaxed, smiling. Suddenly, Voldemort felt something, his eyes opened wide and he fell to his knees. His soundless scream took everyone by surprise, rage can be seen overcoming his face. Dark lord sprang up and pointed the wand at Magnus firing out probably his most emotionally charged Death curse. However, just when the curse was about to hit Magnus, his body disappeared and Harry appeared in his place. The killing curse hit the boy-who-lived full force sending him flying a few meters.
Magnus calmly emerged from the shadows of the Voldemort and broke his neck. After which he calmly burned the body to ashes.
After another wave of his hand, Silencio was taken off, and sounds slowly returned back into the hall.
"Granger help Potter to stand up. He is still alive," seeing Dumbledore wanting to say something, Magnus continued, "All of his Horcruxes were already destroyed, including the most hidden one. So, yeah. Dark lord no more. You are welcome, old man."
After saying his part Magnus simply apparated away.
***
The boy still has some links to the world. But after a day or two, I can safely extract all of the destiny energy out of Potter. He won't need it anymore, but I can use it to gain more knowledge about this world.
"Master, time to ..."
***
In the following year, I solidified my position on this planet, becoming a shadow king of the world.
Britain's magical world started a new page of its history with no Dark Lords left and Harry Potter becoming a savior of the world. A few days after the great fight, I talked with both Hermione and Potter. I asked them not to tell anyone it was me, the one who killed Voldemort.
Although they didn't want to accept it at first, a bit of persuasion did a trick. I mean with my system's speech I could've persuaded Voldemort to raise horses in grassy plains of Mongolia, becoming a herdsman. And they already made sure others won't speak too much about it. After that, I left saying some side character type of shit like, "I was but a ghost of real and now is the time for me to find my peace. I bless you, blah, blah, blah.". You get the point.
Then I made some good old illusion of me dissipating into motes of light in the air and done.
Also, that talk in the first place wasn't specifically to hide my existence and to leave a good last impression. The main purpose was to collect all the destiny energy from MC.
With all of these done, I mostly finished with this world.
After a few more decades I will collect all required information and the main vessel should be ready, so I can safely leave for the other worlds.
It seems like only boring stuff is left to do, huh?