Prologue

Realm of death

Time: Non Existent

Death, one of the most formidable beings in the multiverse, was heartbroken yet again. The agony, pain, and humiliation Death endured were beyond words. A mere mortal would have been driven mad by the events of the last couple of eons.

The source of Death's distress? The Mad Titan—Thanos.

Once more, Thanos had gathered the Infinity Stones, claiming victory in his twisted game. It all began when Death chose a mortal as her plaything.

In her countless years, Death grew weary of solitude and tired of living beings cowering in fear of her. The last intriguing event in the cosmos was Knull's rampage, where he slew Celestials left, right and Centre. It was a thrilling time for Death, finally able to claim Celestial souls. Even she found satisfaction, for the Celestials had shown no regard for life and death. While Death had no issue with their creation, she abhorred resurrection—especially since the Celestials had evaded death in the prior universe. Thus, when Knull embarked on his crusade, Death took a front-row seat and relished the chaos. Alas, all good things came to an end with Knull being trapped, and her monotonous existence resumed.

Later, the next intriguing development was the emergence of Thanos, a titan-deviant hybrid. Death manipulated him into falling in love with her, but when she grew bored, she struck a deal with him to be rid of him. Death told Thanos that only a mortal who achieved equal power to her could be her lover. Thus, Thanos embarked on a quest to become a supreme god.

As Thanos slaughtered planets and sought the Infinity Stones, Death remained indifferent to his actions, but other cosmic entities took notice. One such entity was The Phoenix. When Thanos targeted half of a planet, including an Avatar of The Phoenix and The Phoenix was furious. Unable to directly confront Thanos-a mortal, The Phoenix appealed to the Living Tribunal to hold Death accountable for her games with Thanos.

The Living Tribunal deemed Death's actions wrongful and imposed a punishment: Death was condemned to live a mortal life, unaware of her immortal nature, on a planet of her choosing. Furthermore, the Living Tribunal enforced Death's declaration that a mortal who became her equal would become her lover. To fulfill this, Death was tasked with creating a quest for mortals to achieve her avatar status or equal power within 10,000 years of Death's birth in that world.

Death chose to live a mortal life on Earth outside the Marvelverse, where she had three sons with magical abilities. These sons founded a clan known as "The Peverell," which became so feared and powerful that its name persisted as a bogeyman among other purebloods for centuries. Death's mortal life came to an end when one of her grandsons unknowingly sacrificed her in a ritual to attain magical power, unaware of her true identity.

After centuries, Death decided to entrust three powerful items, known as the Deathly Hallows, to the current Peverell brothers, each imbued with a curse and tied to the quest of becoming Death's Avatar or equal. Death believed that no one would successfully master all three objects, ensuring her eternal embrace. Additionally, she ensured that Thanos would never discover the planet where the Hallows were hidden and thus become her equal.

For 5000 years, the Deathly Hallows became a myth throughout the multiverse—a chance for individuals to ascend to near-omnipotence and omniscience by becoming an entity's equal. However, Death's belief was shattered when Harry Potter, a descendant of two brothers, united the Deathly Hallows and willingly sacrificed himself for others satisfying the conditions. This act made Harry the sole Avatar of Death, returning to life without understanding the full truth.

Over the course of 20 peaceful years, Harry became Death's lover and the only Avatar of Death. However, this arrangement ultimately led to comeuppance for Death due to her past dealings with Thanos.

After centuries of patience, meticulous planning, and widespread war that claimed billions of lives, Thanos accomplished the seemingly impossible task that not even the Elders of the Universe or elder gods had dared to attempt since the dawn of time. He successfully united the six Infinity Stones within a specially crafted Infinity Gauntlet made from a combination of magical and technological URU, fulfilling Death's challenge to become her equal—a Supreme God.

Upon entering the Realm of Death, now endowed with omniscient knowledge, Thanos grasped the true nature of Death's machinations and the purpose of his entire existence. Filled with unprecedented wrath and understanding, Thanos subjected Harry to countless deaths and resurrections in unimaginably cruel ways, each time more torturous than the last. Despite Death's own anguish at the torment inflicted upon Harry, she was powerless to intervene directly since both were mortals, not yet cosmic beings.

Death was deeply troubled, realizing that even if she could intervene, defeating the gauntlet-wielding Thanos would be a monumental challenge. Connected to Harry, Death keenly felt every moment of his suffering under the relentless cruelty of the Mad Titan. She struggled to shield Harry's mind and soul from the brink of insanity as he endured death after death.

Harry, as the avatar of Death, possessed formidable power but lacked experience in cosmic conflicts. In each iteration, he valiantly attempted to overcome Thanos, only to meet a painful demise every time. Witnessing Harry's unyielding hope and unwavering determination, Thanos decided to introduce his own twisted game.

Utilizing the power of the Gauntlet, Thanos reset the universe to the day Harry lost his parents and first encountered Death, forcing him to relive his entire life repeatedly. With each loop, Thanos united the Infinity Stones and retained memories of previous iterations, while Death, unaffected by the time reversal, informed Harry of the impending showdown once he ascended as the Avatar of Death.

Harry gradually began to recall his past lives as he entered the Realm of Death anew. Throughout countless loops, Harry explored various strategies to achieve victory, yet every path led to the same harrowing conclusion.

Many Loops later…

Death gazed upon her beloved, Harry, after enduring countless cycles of suffering, and responded with a heavy heart, "No, Harry, I cannot intervene. This is beyond my reach."

Harry, desperate for a solution, implored, "Can you at least send my memories back to the beginning of this loop? I might stand a chance against Thanos if I have a head start. Every time I become the Avatar of Death, my power level stagnates. No rituals or enhancements seem to work anymore."

"I can send memories and even souls back, but I can't do it for you while Thanos uses the Gauntlet to send you back," Death explained apologetically.

Disheartened, Harry's eyes widened as a new, wild idea took hold. "Death, what about another Avatar of Death? Could you bring someone from another multiverse to aid me?"

Harry looked death dejected, it was the last idea he had to escape from this hell. His eyes widened as he had an another insane idea. His "Death" is the primary Cosmic being of the concept of DEATH, therefore has the entire knowledge of multiverse and meddle in it, if required.

Death was intrigued by the idea, "Harry, while I can do it, there are no other universe in which I create true deathly hallows. The wand, the Cloak, and the Stone exists, but it's not created by me like this universe. Every other multiverse has a Death, but it's just different aspects of me. I only have you as my Avatar."

Harry pleaded to Death "It's not a problem, please send a powerful harry as my twin brother or one of my friends or anyone with the required knowledge. Please do it Death, we can't suffer anymore and even the world is stuck in this circle. I have one more insane idea Death. Countless number of times I have travelled this world for an advantage and help, but nothing is enough. Infinity stones cannot be found by me since Thanos wishes for me to not find it when he sends me back. Infinity stones of this world only work in this universe. Let's change the universe when he sends me back again. Let's merge some new universes where powerful beings are there and even when Infinity Stones go back it will be updated to the new universe and the order placed by Thanos will be nullified and I can find them."

Death was surprised. In her long-long existence, it was second time she was surprised. It is ironic since first surprise came from the success of Thanos in becoming a supreme God. Death wondered whether her shielding of Harry's mental faculties was actually a success or not. To merge universes is not something even a cosmic being such as herself could do without consequences. She has the power to do it, since she has omniscient presence in every multiverse.

Death said "Harry, in the next loops travel through Universes and decide which ones to merge with your universe. You can do by using America Chavez easily after arriving in Marvelverse. Otherwise, the hard way is also there. I must talk to my elders about this."

Lady Death sought permission from The Living Tribunal to merge a couple of universes, but the Tribunal was displeased with this audacious plan and prepared to punish her once again. However, at that moment, the One Above All (OAA) intervened.

"Enough with your punishments, Tribunal," OAA declared. "It was your punishment that paved the way for a mortal to ascend to the level of the multiverse." OAA turned to Death, acknowledging her plight. "Death, you have my authorization to take whatever measures necessary to address this Thanos situation, but remember the cosmic rule of non-interference. Thanos is now on your level, and it would be catastrophic if he grows bored and seeks more power from entities like the Beyonder or the Anti-Life Equation. He may even pose a threat to me."

Death nodded solemnly, understanding the gravity of the situation. "I will proceed with caution, One Above All," she replied.

With the blessing of OAA, Death began to contemplate her next move, knowing that the fate of the multiverse rested on her ability to handle Thanos's newfound power and ambition.

In the following loops, Harry travelled through various multiverses, where Thanos doesn't even exist and learned many secrets of various so called Superheroes. Harry was very impressed by two alien beings who may become the most powerful mortal in their universe. He even travelled to the universe from which Thanos originates the so called 'Marvelverse' and committed so many crimes to learn everything about various powers in it. The accumulation of such vast knowledge was unheard in the cosmos.

Many Loops Later…

Harry appeared before Death in this loop, ready to enact his plan.

"Harry, Harry, so nice to see you. Do you have a plan? Which universes do you intend to merge?" Death inquired.

"Yes, my dear. I've decided," Harry replied confidently. "Merge the Marvel, DC, and Invincible universes into my own."

"Marvel and DC I can understand Harry, there methods to acquire powers in those verses, but why Invincible? Why do you need those war thirsty sociopathic washed out Kryptonians when you have the original?"

"It's precisely because of that I need that verse and of course to acquire the power of Viltrumite's adaptation. I need sociopathic warriors, after all Thanos has an Army of Trillions."

" Interesting… So you only need Viltumites for an Army? Harry, please be careful, DC has it's own powerful beings that may endanger your plans."

" Yes, but I need Mark Grayson too. So please make sure he exists. I will be careful of dangers my dear."

"Ok, I will merge the universes as requested when Thanos turns back time to sent you without memories to the night of your parents death. The moment the killing curse touches you I will merge the universes past, present, future and uses the changes to insert your current mind and soul in your 1 year old self. I don't know when your body will adapt to the change, until then it will be very painful".

"Wait, so you're saying even my past will be altered? Could you make me a mutant too?" Harry asked eagerly.

" Yes, I can merge the worlds history and make you a mutant, but the power I cannot guarantee. It's truly random. I can influence it of course, by making your mothers family a prominent mutant family."

Hearing this, there was a truly a monstrous smile on Harry's face as plans after plans were made and discarded using advanced occulumency. Seeing the smile even Death itself get a chill down her spine, after all knowledge is power and Harry has the entire history of the 3 multiverses and can now manipulate it as he wishes before he starts his latest journey.

Prime verse

Oct 31st 1991

Godric's Hollow

Lord Voldemort sneered down at the dead Lily Potter. 'Foolish girl should have used my offer and stand aside. Poor Severus, he can choose some other redhead even though they may be pale in comparison to Lily, even I can see how attractive she is.'

Voldemort looks into the crib and saw a one-year-old looking at him. Voldemort felt like the green eyes were looking through him and suddenly he felt a minuscule presence behind him and turned, a Mage shield already beginning to form, but there was nothing there. Voldemort laughed to himself and turned to cast.

"Avada Kedavra"

Voldemort watched with a crazy grin as the pale green light of death travelled slowly toward the child and hit his forehead and

The Universe stood still for a second..

Authors Note: A crossover story that has been inspired by many other stories I have read. It's a muse that has been in my mind for many years. this was the first fanfic I started writing, but I immediately understood it was over ambitious in that and started other smaller ones. Just cross posting here too!! 

to read chp 1 which is free as it is available in FFN and AO3: https://www.patreon.com/collection/568578?view=expanded

to read chp2 : https://www.patreon.com/collection/568578?view=expanded