Backstory
The almighty godly being called The Void God was born long ago from nothing in the Infinite void as times passed, he became old and powerful when the Infinite Void was still a empty void without any trace of life there was other younger similar being such as The Void God in the infinite void, they are a lot weaker and smaller and treat him as their senior and leader.
Not even The Void God himself who was the first one to appears knows how many of them there is and from where or how they are born, but he knows there is a lot of them and they are mostly in the deepest part of the infinite void.
The only different living being he knew existed ever since he was born was strange tiny little man wearing green clothes, he was mostly inactive and sometime he could stay still without moving for billion of years and some other time was exploring the infinite void without any purpose or goal.
The Void God was quite curious about him, but was mostly ignored by the tiny being all he could get out of his mouth was his name is Achille.
One day Achille created the very first multiverse in the Infinite Void and soon after many other gods appears out of no where and started their own little multiverse.
His corruptions
Curious he left his family the other void gods and travel for hundred of years to examine these new life forms and as he was trying to figure out what was that giant black sphere which was a universe, he accidentally touch it and in a second he vaporized the universe and absorbed all of it.
This awakened something inside The Void God he suddently felt stronger and full of energy and was completely overwhelmed by this feeling of ecstasy, he stayed there for a while lost in his thought as he suddently felt this feeling slowly disappear.
He wanted to feel this intence sensation again and as he was about to touch another universe this time was stop and attacked by a god who immediately tried to destroy him.
The Void God was never attacked or got into a fight before, so he didn't know what was hapenning The Void God was confuse when he feel the anger coming from the god attacking him as he couldn't understand emotions, The Void God suddently wanted to destroy him to hurt him as he became blue and unleashed a giant cloud which vaporized the god and his whole multiverse in mere seconds, The Void God absorbed all of it and this time he felt something different, it was the same feeling of ecstasy, but mix with emotions mostly anger and fear.
They were the very first real emotions The Void God felt it deeply affected him and changed him, he was shock by this event and flee and hidden for two thousand years, during those years he could feel his power slowly leaving his body and he was becoming weaker and weaker and this feeling of fear grow inside him every years since he could no longer meditate and recover his energy and felt as he was dying and craving for something so much he was in constent pain and he became angrier and angrier about this situation.
(He didn't know, but he was actually dying from hunger, after absorbing the god and his multiverse his body became addicted to it and without it, he would eventually die and disappear in maybe 1 or 2 million years.)
Stronger than ever
When The Void God became weaker that he originally was ever since he was born he knew his situation was serious and he needed to do something or else he wouldn't last long, so he explored the Infinite Void and sensed a region with a lot of multiverse and he realize what his body was craving for when he saw a multiverse.
Parts of his body was literally deforming and going toward the multiverse, when he came close to it he immediately unleashed a giant blue cloud and vaporized everything and absorbed all of it and he felt much better as if suddently a huge hole was filled inside him.
From this moment he when on a genocide and killed and absorbed hundred of gods and multiverse with each kill he grew in power and size, he originally was the size of a few universe but now he was the size of a multiverse and was stronger than ever, after absorbing another multiverse he suddenly sensed a huge energy source coming from a rather large multiverse in another region.
A Well Defended Multiverse
He when toward the multiverse and was immediately stop by hundred of powerful beings, none of them were gods capable of creating multiverse, but they were all extremely powerful there was a giant being of light, and multiple very small beings the size of humans some other a lot bigger, some wearing green or red clothes others using strange triangle shaped object to power themselve up and a whole armada of huge spaceship the size of multiple galaxies.
The battle when on for three days The Void God killed and absorbed them all one by one even if there was no way for them to win they were not giving up as if all they tried to do was slow him down waiting for something to happen or somebody to show up.
Only one survivor was still standing, The Void God was surprise to see it was a mortal with an extraordinary power he was stronger that most of the gods he killed so far in the infinite void and even stronger than the giant being of Light he recently absorbed which was obviously their leader.
He battle continue for few minutes until the mortal being surprise The Void God with a technique that created a giant sphere the size of a universe that started to suck him in, The Void God was completely absorbed into the sphere and appears in a strange dark void.
Suddently billion of light striked him from all directions and he felt his power being drained from him, he quickly reacted by unleash all of his power in a giant burst which literally broken the strange dark void he was inside, the giant sphere explode wiping the whole multiverse and a part of the region in the process.
The Void God was free and saw the mortal completely out of energy and seriously injured by the explosion The Void God was about to absorb him when he died and turn into dust, shortly after this battle The Void God was pissed because not only he couldn't absorb the juicy multiverse, but also lost all the power he gained from absorbing the powerful being during the battle.
His defeat
The Void God was pissed by what just happen, but as he was complaining not paying attention he was hit by a giant sword made of energy and for the first time ever in his entire existence he was injured as he saw his body being impaled, The Void God was completely paralyze as it was the first time ever he felt real pain he saw what seem to be his blood pouring out of him.
The Void God saw the huge sword was hold by a tiny little being the size of a normal human wearing green clothes, he quickly realize it was the being called Achille and he looked extremely mad, The Void God broken the energy sword and immediately unleash a giant blue cloud, but Achille seem to be barely effected by it as he pushed the cloud away with a simple mouvement with his hand.
Achille charged The Void God and quickly created a giant energy shaped like a frypan and hit The Void God and send him flying far away and Immediately teleport behind him and smash him again and again in all direction like a giant tennis ball each hit creating shockwave strong enough to wipe out multiple multiverse.
The Void God was barely able to resist the hits without getting injured and was able to stop one of the attack and destroy the giant frypan and counter with a huge beam attack that directly hit Achille, but seem to have no other effect on him only destroying some of his clothes.
The Void God never imagine somebody so powerful could ever exist, he knew he was too weak to win, but if he can damage Achille clothes maybe with more power he could actually hurt him, Injured and weaken The Void God decided to flee for his life, for some reason Achille didn't go after him and let him escape only looking at him with a huge smirk on his face.
Plotting his revenge
The Void God was defeated and broken as for few hundred years he flee deep into the infinite void, to where he was born he was greet by his family the other Void Gods who were surprise and confuse to see their senior and leader in such state he was weak and injured.
The Void God could link himself to the other Void Gods mind and in a matter of seconds they were all greatly influenced by him sensing his emotions, his anger and pain and his memories they all slowly became like him and decided to help him, to heal him multiple Void gods merged with him "patching" his damages parts healing him but The Void God notice not only he was healed, but became stronger in the process and felt the same feeling as when he absorb the multiverse and so got the idea to merge with more of them for the sole purpose of growing in power.
For few billion years he gathered and merged with a unimaginable amount of Void Gods he became infinitely stronger until he could no longer merge with them, maybe he reach his limit or maybe there was was too big? As he was now the size of hundred multiverse, either way it was time to strike back and get his revenge as what seem to be a infinite amount of Void Gods of various size and power followed the gargantuan Void God leader to wars.
The Great Gods Wars
Few hundred years later the enormous army finally reach a part of the infinite void with life as like a swarm of lotus they destroyed everything in their path as a big region with thousand of Multiverse were completely obliterated once the region was clean they travel to the next region where The Void God was defeated by Achille.
As the huge army of hungry Void Gods arrive they are greet by an army all line up ready to fight them off there was few hundred thousand if not more of them, but not all of them were gods and many of them were what seem to be the strongest heroes of all the different multiverse and their gods.
The Void God immediately located Achille amount them and advance torward him, Achille explain to the other Gods he could easily wipe out the whole army, but he want to keep all of his energy for their leader and their role is only to hold them back for as long as their can to protect their multiverse, once he defeated their leader he would help them to defeat the rest of them.
Achille teleport The Void God leader with himself inside a giant indestructable sphere far above the battlefield to fight him one to one as the other two army charge and ram each other as many explosion and flash appears everywhere.
The heroes quickly realize the Void Gods are very powerful, but not invincible many dies on both side, but due to their team works and amazing techniques the heroes slowly start to take the upper hand as many of the Void Gods are fighting each other to see who get to absorb the injured gods and heroes.
The battle goes on for a whole month and finally the final Void Gods is slain and disappears the heroes scream victorious, but quickly realize it's not over yet and they see far in the distance another army of Void Gods coming at them the army is 10, 30 if not 50 times larger that the last one.
The survivors of the last battle look at each other many heroes are completely out of energy and their number got from few hundred thousand to merely a thousand still standing, they know it might be the end as many of them look above their head and see the huge sphere where Achille and The Void God leader disappear to.
The Gods Wars Ending
We see inside the giant sphere Achille and The Void Gods still fighting each other, Achille is visibly tired with few bruise and his clothes are rip apart and The Void God completely exhausted and losing energy at an extremely rate at the beginning of the fight both of them had what seem to be a Infinite amount of power, but The Void God unable to absorb anything and using all of his power 100% of the time since a whole month he was getting weaker and was unable to kill Achille and for the first time since the fight begin The Void God lost his focus and was lost in his thought.
Achille took this to his avantage to literally enter The Void God going to his very heart and start to absorb all of his energy, The Void God size quickly reduce and all of his power was drained he was obviously defeated, Achille break the giant sphere and see at the very last moment the giant army of Void Gods second away from getting to the weaken army, Achille unleash all of his power and completely vaporize all of them in an instant the battle was officially over.
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To give you a small idea of what the battle would actually look like watch this small video. (Example)
"Renplace the Anubis dog monster army by Void Gods and the guys on horse fighting them with the gods and the heroes army fighting the Void Gods and obviously imagine them fighting in the infinite void with giant beam attacks and other crazy techniques"
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The Void God Fate
After his second defeat this time Achille wouldn't let him go as easily, he spared The Void God life in exchange he would help Achille to locate all the other Void Gods and with The Void God help Achille would hunt and destroy all of them to avoid any other wars.
For over 186 000 000 000 years Achille with the help of The Void God found and defeated all of the Void Gods one by one when Achille was satisfy he gave The weaken and slowly dying Void God two choice...
1: Achille leave him here to his fate and goes back to his multiverse.
2: Bring him back with him, but he would from now on serve him like a slave.
3: Achille gave him a quick death.
The Void Gods replies: "So slavery or death huh?" The Void God look at Achille and choosed number 2.
Achille came back to his multiverse and was happy to see it was still there intact and full of life as The Goddess of Life did an amazing job while he was gone, he explain to her that The Void God shall now live with them his job would be to keep the void around the universe clean and also serve as a guardian to stop any mortals from traveling between universe.
From this point on The Void God was barely able to survive and slowly, but surely gain his energy back by killing, destroying and absorbing anything that came out of the universe no matter what it was, this is where his story ends for now.