Xandar
With a sudden pop, the man materialised inside the Nova Corps vault. He was tall, with strikingly long hair and beard. He was dressed in robes, with a wand in his hand and a golden gauntlet on his hand. Moving with determination, he stepped over to the subject of the vault, an orb contained in a glass case.
Raising his wand, Dumbledore caused the case and the orb to shatter, revealing a glowing, purple stone, which he took and placed on the gauntlet. In that instant, alarms and sirens started blaring, as futuristic automated weapons deployed, aiming themselves at the intruder, but by the time they started firing, he had long since Disapparated.
The Statesmen
Thousands of light years away from Xandar, the Asgardian ship travelled calmly and silently. In the ships cabin, Thor and Loki stood talking quietly, until Albus Dumbledore materialised right in front of them. Confused, Thor turned to him attempting to ask him who he was, but Dumbledore only had ears for Loki.
"You are Loki Laufeyson, yes?" the headmaster asked the Frost Giant.
"Well, yes I, wait, but who are you?" Loki stammered as Thor continued to try and enter the conversation.
"It does not matter. What does matter is whether you have the Tesseract with you right now."
Thor finally made himself heard by Dumbledore, "Sorry, but the Tesseract was destroyed on Asgard, when Surtur destroyed it. Now- "
Dumbledore interrupted the Thunder God, smiling serenely "Well, you see, it would have been, but your mischievous brother here had decided to take the Tesseract with him, as he fetched the Eternal Flame. And he has it with him here now."
Loki was now sweating bullets, stammering excuses at an angry Thor, but Dumbledore simply sighed, drew his wand and said, calmly: "Accio Tesseract." In a flash, a blue, glowing cube flew from Loki's pocket into Dumbledore's open hand.
"Thank you." He said to no one in particular, as he pointed his wand at the cube in his hand, making it shatter in its place. The pieces all dropped to the floor, all except one, the largest of them, the Space Stone, which instead was levitated into the next available position on the gauntlet. Satisfied with his work, Dumbledore proceeded to Apparate to his next location, leaving two very confused god-brothers behind.
Knowhere
The Collector was known to be a very busy man, ruling most of the underworld in Knowhere, and infamous for collecting many valuable treasures, the crown jewel of which was the Aether, or, as the Asgardians who delivered it knew, the Reality Stone. It was this stone that had drawn the presence of Albus Dumbledore, who now had a gauntlet with two Infinity Stones and a habit of Apparating directly to where he needed to go.
Materialising in the direct vicinity of the Collector himself, Dumbledore wasted no time in flicking his wand and placing the man under the Imperious Curse. Without a word, he scurried over to his machines, and in minutes had presented the Reality Stone to Dumbledore. Using his wand to levitate the stone into the gauntlet, he let it click satisfyingly into place.
Deciding to use the new stones he'd acquired, he closed his fist, making the blue Space Stone to glow brighter than the others. A portal made of clouds and lightning opened just behind him, before closing in and engulfing the professor.
Hogwarts, Potions Chamber
A portal of clouds and lightning opened in the empty chamber belonging to the Potions Master, revealing the headmaster of the school it was situated in. Dumbledore noted that the Stone could bypass Hogwarts defensive enchantments with no issue, and that Severus was not present in his office.
Raising his wand, Dumbledore said quietly, "Accio Veritaserum".
With a clatter and a bump, a glass vial of a clear potion flew from one of Snape's many hiding places into Dumbledore's palm. Opening another portal, Dumbledore vanished once more.
The Benatar
Appearing in the nearly empty room of the Guardian's of the Galaxy's ship, Dumbledore wasted not time firing of two Stunning Spells at the room's occupants. With loud thumps, Gamora and Star Lord fell to the floor before they had even registered that someone else had entered the room.
Turning around, he waved his wand across the room, closing and locking all the doors and entrances, before suddenly, a large, angry man lunged at him, wielding two daggers and yelling loudly. Without hesitation, Dumbledore closed his fist, this time making the Reality Stone glow brighter, as Drax transformed into a little bowl of Sherbet Lemons.
Dumbledore turned again to the unconscious green woman and knelt down to pour the Veritaserum into her mouth before standing up and casting Incarcerous and Renervate, one after the other. Suddenly, Gamora woke, and began lashing out and yelling indiscriminately.
"Excuse me," Dumbledore asked calmly "Can you tell me where the Soul Stone is?"
"Yes," Gamora responded harshly.
"Where can I find it, exactly?"
"On Vormir,"
"And how do I acquire it?"
"You need a sacrifice."
"I see, thank you for telling me. Obliviate." He stood up, having removed all her memories of the last five minutes, and open another portal, being unable to Apperate this time.
Hogwarts, Umbridge's office.
As the portal closed and his vision cleared, he spied Harry Potter trying to throw Floo powder into Umbridge's fireplace. Approaching the child, Dumbledore grabbed him by the arm and promptly portalled to Vormir, before anyone could say anything.
Vormir
Appearing on Vormir, Harry immediately started asking Dumbledore a bunch of stammered questions, but was silenced when Dumbledore raised his hand.
"Quiet, Harry. Your questions will be answered, in time. For now, stay quiet, and stay by my side." Dumbledore told him quietly.
And so, they walked across this foreign planet, up to the mountain, which seemed to be the only noticeable landmark for miles around. As they climbed the path up the mountain, they where eventually met with a cloaked, floating man, not too unresembling of a Dementor.
"Welcome, Albus, son of Percival. Harry, son of James." The Red Skull greeted, his voice echoing eerily.
"Wait, professor, does he know us?" Harry whispered to Dumbledore.
"It is my curse to know all who travel through here." The Red Skull answered for him.
"And the Soul Stone is here?" Dumbledore asked him.
"You must know, it asks a terrible price."
"One I am willing to pay"
"They all think that at first," he shifted so that his face was visible in the light, "They are all wrong"
Dumbledore and Harry walked with the Skull to the cliff face, as he recounted the story of how he was cast there by the Tesseract. When they reached the edge, he turned to them.
"Here lies what you seek, along with what you fear. The Soul Stone holds a special place among the Infinity Stone's. One might say it has a certain… wisdom to it. To ensure that whoever seeks it understands its power, the stone demands a sacrifice."
Dumbledore looked at him, already knowing the answer "Of what?"
"In order to acquire the stone, you must lose that which you love. A soul, for a soul."
Harry looked up, a grim realisation hitting him. "Professor don't tell me…" his voice trailed away in fear. He tried to walk away, but he had walked towards the cliff-face while the Red Skull was talking, and Dumbledore had stepped between him, and the path down, trapping him.
"I'm sorry, Harry." Dumbledore whispered, a single tear falling from the eyes framed behind the half-moon glasses. Slowly, mournfully, he brought his wand down on the boy, as he whispered "Avada Kedavra." Green light illuminated the area around them as Harry was knocked off his feet, over the edge of the cliff, suspended in air for an instant, before falling down the cliff, out of sight. Lightning flashed above, and Dumbledore found himself lying in a puddle, with the Soul Stone in his hand.
Titan
Emerging from the portal, Dumbledore surveyed his surroundings, a dusty, ruined planet, with giant structures on the horizon. In front of him sat a man a third his age, also wearing robes, albeit ones with a different style, fiddling with a rock, he was the other sorcerer. Dumbledore knew then and there that he could not defeat him with his powers in a conventional battle, but then again, he did not need to.
The sorcerer spoke up. "Yeah, your much more of a crazy wizard professo- "
"Imperio" Dumbledore interrupted. The Sorcerer Supreme fell silent, his eyes unfocused. Without speaking, he conjured the Time Stone, and levitated it towards the wizard. Placing the stone in his gauntlet, Dumbledore noticed a large shadow over him rapidly darkening, and looked up in time to see a giant pillar being thrown down at him, barely giving him enough time to put up a shield with the Space Stone.
With a brilliant blast of energy from the Power Stone the pillar was destroyed, and with a wave of his wand, transfigured into daggers, which then all flew towards Iron Man with blinding speed. Hearing someone behind him yell angrily, he turned to see Star Lord, Gamora and Mantis attempting to rush him. Using the Space Stone to generate a shield, he cast a non-verbal Bombarda Maxima at the trio, the explosion engulfing them in flames.
He turned his attention back towards Iron Man, raising his wand, but before he could speak, a sticky, web-like substance stuck to his mouth, and then a web stuck to the gauntlet, pulling his arm away from him and not letting him close his fingers. He turned to look at who had shot the webs, spotting Spider-Man a few meters away. "Can't use magic if you can't speak" he joked. Pointing his wand at the web attached to his gauntlet, he cast a non-verbal Diffindo, snapping the web. Spider-Man then cast a web in an attempt to escape. Ripping the web off his face, Dumbledore bellowed "Avada Kedavra", at the spider, the jet of green light striking him in the chest.
Behind him, a whistling sound warned him of incoming projectiles from Iron Man, and immediately created another shield with the Space Stone. As the explosion erupted around him, Dumbledore transfigured the fireball into water, and threw the ball of shimmering liquid at the Armoured Avenger, knocking him out of the skies and trapping him in the water, which was promptly transfigured into molten lava.
"As impressive as it is, that armour of yours can't survive in there forever." Dumbledore stated quietly. As he turned to walk away, he pointed his wand at Strange, and shot a bolt of green light at him, causing him to fall. With a swish, the Cloak of Levitation flew at Dumbledore, who merely muttered "Incendio" causing the Cloak to burst into flames and crumple.
Wakanda, Shuri's Lab
The portal opened upon the remainder of the Avenger's, Captain America, Black Widow, Wanda, Vision, Shuri, Black Panther and Okoye, in the Wakandan Lab. Emerging from the portal with a look of determination, Dumbledore stared them down, before smiling and asking for the stone.
"We can't do that, Vision too important." Cap said, preparing for a fight. Wanda began forming orbs of Chaos Magic at her hands. "You'll only get that stone through force over my dead body."
Dumbledore sighed. There'd been enough bloodshed today, but it looked as though he had not choice. Clenching his fist, the Reality Stone flared up, and Wanda was immediately transformed into a Puking Pastille.
Black Widow drew her guns and immediately tried firing at Dumbledore, but the gun and its bullets became Cockroach Clusters when the trigger was pulled.
Waving his wand in an arc around him, fire encircled him, incinerating Captain America, Black Panther, Shuri and Okoye, before the flames shot at Black Widow.
Vision, now the last one left, feebly attempted to stand up, and fired a laser from the Mind Stone at Dumbledore, but a flick of his wand and a quick Shield Charm stopped it in its tracks. Pointing his wand at Vision, Dumbledore smiled and cast the last spell he needed: "Vera Verto" At that moment, he watched as Vision shrinked away, and turned into a decorative, glass water goblet, with the Mind Stone sitting inside.
Picking up the goblet, Dumbledore tipped the stone into his hand, before placing it in the Gauntlet. Smiling at his finished creation, he counted the stones, checking to see if he missed any, Power, Space, Reality, Soul, Time and Mind. Satisfied, he Disapparated with a pop.
Hogwarts, Umbridge's Office
Stepping out of the portal, Dumbledore was met with the sight of Umbridge's cat-clad office, Umbridge herself, and the Inquisitorial Squad holding the Dumbledore's Army members hostage. At his sight, Umbridge went stone white and began stammering. Hermione jumped and began asking questions faster then she could breathe. "Professor, where've you been? Where's Harry? What's on your ar- ". Raising a hand, Dumbledore silenced her. "Don't worry Miss Granger," he held up the gauntlet, all the stones glowing at once. 'Now, reality can be whatever I want." And as Umbridge shrieked "No", Dumbledore pressed his fingers together, and snapped.
