The story of the seventh stone was from Earth-616, rather than the Infinity Gems being born from the birth of the universe itself, they were born from a multiversal cosmic being who committed suicide in the primordial era of Earth.
Nemesis was lonely, she was the only being in existence at this time, so in her depression she committed suicide, her aspects were then split into seven Infinity Gems that contained aspects of her powers, granting whoever held them the power over her aspect contained within the stone.
Upon the creation of the stones, the Ego Gem, which held the majority of Nemesis' consciousness, her ego, the white gem was lost, it was somehow transported to another universe, Earth-93060, while the other stones remained within Earth-616.
This is the true source of the will's within the gems, not a universal will like in the MCU or other versions of the Infinity Gems. The source gems were Nemesis, so once Adam did gain all the stones in the MCU, or Earth-19999, they would no longer be this universes knock offs.
The Ego stone was pulled into this universe the moment Adam took possession of the first stones and connected to them, she was pulled in by the Space Gem.
You see, in the comics, the will within the Time and Reality Gem's rebelled against Nemesis, which is what led to her being defeated, but the others didn't, so when the Space Stone was becoming the Space Gem, it pulled the Ego Gem from the Ultraverse. Bringing it into the Adams universe.
Adam's mind raced at this implication, Nemesis could possess people using the Ego Gem, rather that granting the holder of the white gem power like the others, Nemesis possessed them and supplanted their consciousness, effectively killing the host but at the same time not.
She would be the dominant personality while the previous one would just meld into her own, echoes of the previous mind made in hard to focus her actions, the wants and desires of the host confused her motivations, which slowed her progress to her goal in recombining with the other six gems.
But the more gems that were collected together, the stronger and more focused she would become, so once the six came together, her consciousness will fully be awakened. As long as Adam didn't collect all the gems, he could prolong his confrontation with Nemesis for an extended period of time.
This was what the Ancient One was hoping for, that Adam would stay content with the four he currently held, as long as he kept the four and left two, Nemesis' progress towards Adam would be even slower than if he held five.
This however didn't deter Adam, he also knew the truth on Nemesis, those like him who knew the story, knew that the Nemesis was dead, what was actually inside the Ego Gem was more similar to Eve or Jarvis, an AI that Nemesis had created within herself to help curb her loneliness, she was the only being in existence at the time, plus the AI could help her accomplish tasks using her powers.
So she wasn't as powerful as the original Nemesis, still extremely powerful, but not on a multiversal level like her original body. This was due to the changes in the other six, two of which worked against her rather than just doing as she wished. This allowed the Avengers and Ultraforce to defeat her in the end, so Adam didn't let fear cloud his judgement.
Rather, Adam's mind began to calculate and begin to prepare for her, as long as he wasn't entirely blindsided, he felt he had the capabilities to overcome anything.
"Thank you for the warning, although I won't be making the oath you asked for, I will promise not to retrieve the Soul Stone until I am ready for her. She is not what you imagine her as. She is but a shadow of the past, although powerful, she isn't as unbeatable as you think." Adam turned to look down at Ancient One who was much smaller than him since he did take a astral form to converse with her.
Although he looked like himself, he was much taller in his astral form, he was the same size as Didact, all 11 feet towering over the Ancient One. He enjoyed the look she gave him as she pondered his words carefully, she was learning much in this interaction with Adam, seeing him as a wealth of knowledge.
"What is your goal here Adam? I mean in my universe as a whole. What will you do with the power that you gain? Before I make my choice I must ask this, speak only truth for I will know if you tell lies." Ancient One looked up into Adam's eyes as she spoke.
"Honestly, goals are constantly changing, what I seek now may not be the same in the future. Is that not the point of goals? Work towards them, while always raising the bar. I can't tell you my ultimate goal, for I don't really have one, yet. As it is though, the multiverse is my goal, I wish to explore it, to see what's out there. What strange worlds and universes are out there? I don't seek destruction if that is what you are asking, dominance maybe, but for the better." Adam replied, then using the Reality Gem he began showing different parts of the universe.
"Order to the chaos," Adam said as the images displayed various battles, even showing Thanos wiping out Gamora's home world, along with various other battles both on Earth and off it amongst the various worlds and realms, "that is the goal, and not just this universe, but others as well. To bring them under one rule, Thanos is right in a way, resources are finite, but his way is wrong. Killing half the life only temporarily fixes the issue, eventually the population will raise back up and eventually the same issue would arise. So unless he plans to just continue to do the same thing over and over, it doesn't solve anything." Adam explained.
"And your solution is the multiverse?" Ancient One asked as she began to piece things together.
"Yes, resources are finite within the universe, but their are an infinite number of universes." Adam replied as he began to gaze into the various universes.
"So if you could facilitate trade across universes, you effectively create an infinite amount of resources for those connected finite universes. An impressive deduction Adam, but you seem to be forget about someone, someone who wished to basically do the same." Ancient One once again had to try to get Adam to see his plan had been tried before.
"Who, and don't you dare be implying that maniac Kang the Conqueror, cause it is not the same, he wanted to use the other universes destruction to feed his own universe, giving it the infinite amount of resources because it was stolen." Adam said incredulously.
"I told you about names, He Who Remains, has already taken notice of you, he has been trying to destroy this universe. The mutants appearing in mass, vampires, werewolves, you've even got Ghost Rider brought in now, I do suggest not proving that one, he is a little unhinged at times." Ancient One admonished with a sigh. "You have been causing a lot of problems for me as of late you know. You have changed the trajectory of events without fully grasping the consequences of your actions, there is a reason for events to unfold when they do. If you possess the Time Stone for as long as I have, you would understand. But as they say, what's done is done, I shall deal with my stude.." Ancient One was cut of mid sentence by Adam's resounding voice.
"No. I will deal with Kaecilius, I will give you time to make a choice. But let me warn you, just like everyone else, and as you so elegantly put earlier me as well, there are consequences for our choices. You are right, I may not know fully the changes I bring, but inaction due to fear is just waiting for death. You expect me to leave it to chance and hope me and my crew aren't included in the 'Blip', sure there was a high chance we wouldn't be affected, but could I, or you for that matter, know for sure? Besides, I need that book for a bit, I need a spell from it before I will return it, hopefully when I bring back the Darkhold, you will have made a choice on which way I gain the stone in your possession. Willingly or not." Adam said as his astral projection faded, leaving Ancient One alone to think.
Ancient One sat and contemplated the conversation, gathering her thoughts, replaying it with the time stone and going back, using it to have multiple conversations with Adam. She was getting more insight into Adam, trying to get a read on his personality, just what kind of being he was.
As Adam and her were talking before, her physical body had used Adam's distracted state to cast a spell on Adam's body. It wasn't harmful in anyway, which is why the stones didn't automatically defend or even trigger any instinctual danger from Adam. It was merely an inspection spell, she was trying to find what universe he had came from so she could send them back if ever needed.
What she saw was something she had never encountered, three souls intertwined into one body, two from one universe, but the dominant one was from another. The potential of this soul was immeasurable.
Due to Adam Young being from the Source Universe his soul was the strongest she had ever seen, even the power if a being like Nemesis, who was even above One Above All when she was alive, it was her death that allowed One Above All to create the universe from there, Adam was able to wield her power easily. As if he knew how to use the powers together all along.
Ancient One even had a thought that he was possibly the reincarnation of Nemesis herself, or perhaps a Avatar or Champion. She would need more time to come to a conclusive answer, that wasn't the only puzzle to Adam.
The other two souls and the physical augments done to Adam's body were a mystery, they were similar to warrior spirits. Contained within these souls were bountiful amounts of information, battle experience, commanding, diplomacy, various experiences.
One soul was obviously Didact's Forerunner DNA and the genetic knowledge he had gained throughout his experiences, which included all the knowledge his family before him had gained.
The other was Adam, or at least it would've been had Adam Young's soul not slipped in, what replaced it wasn't the programming for Adam's original consciousness, but all the military training and knowledge required to run a empire in emergency situations. He was made to be the last hope for the UEG and UNSC if ever needed.
After some time Ancient One returned to her body and stopped her actions, she had some deep meditation to do before making a choice.
"Master, why have you stopped? Have you found Kaecilius?" Mordo asked, he was stunned to see Ancient One suddenly stop what they were doing, he had yet to locate his friend.
He was worried for Kaecilius, they had learned together and had grown close, he was hoping to speak to him and get him to stop before he is killed by their master.
"It is too late Mordo, Kaecilius has made his choice along with several others. They have already begun the dark ritual from the book, come along and gather the others. There is much that needs to be discussed, and I am not entirely sure on the exact time we have before the time to discuss is over." Ancient One said as she made her way back to her study.
"So what about Kaecilius? Your just going to let that outsider kill him? Rather than assist him in doing your job, to get rid of other dimensional beings, your going to leave him to die? You are ignoring your own teachings, so what these beings don't come from a dark universe, they aren't from ours." Mordo questioned her harshly, anger could be heard in his voice as he spoke.
Ancient One stopped walking out of the room, turning her head back, she observed Mordo for a moment before replying.
"True, but that ship has sailed. Even with the Darkhold, Kaecilius couldn't kill him, even if I helped him it doesn't guarantee victory, and the outcome that would follow would be even worse whether we won or not. It's a lose-lose scenario. You would sacrifice the world just to hold on to a rigid belief, you have been speaking to Kaecilius too long. I never taught we banish all other dimensional beings, only those that seek to harm or possess. Now come, there are more important matters for us to handle." Ancient One said then continued out of the room.
Mordo hesitated to leave, unsure of what to do. Do as his master told, or work alone to try and save his fellow disciple.