Schism

They train, bond, and brainstorm as much as they can,  as often as they can until one day, Yao says "It's time".

Gamora knows where the soul stone is, and with her permission, Yao uses her power to visualize the location and portal half of the team to Vormir; Tony, Nebula and Gamora because of their strength and firepower, and Loki and Yao for magic (and transportation).

They make their way to the summit and find the Guardian waiting. Not one to mince words, Tony pops up his faceplate and speaks, "So, red and floaty, where do we find the Soul stone?" Eyerolls all around.

"It is here," the Guardian says, "What you seek lies before you. As does what you fear. You should know, it extracts a terrible price."

"What price?" Yao asks.

"Soul hold a special place among the Infinity Stones. You might say it has a certain wisdom." 

"Tell us what is required," says Loki.

"To ensure that whoever possesses it... understands its power.... The stone demands a sacrifice."

The team look to each other, worried, not liking the direction the conversation is taking.  

Gamora speaks, "A sacrifice? Of what?"

"In order to take the stone you must lose that which you love. A soul... for a soul."

Everyone is speechless - they are all shocked. They had no idea they would be facing this - none of the other stones had required anything from any of them for possession. 

"What the hell are we supposed to do with this information?!?" Tony demands, frustrated and a bit pissed off before becoming pensive. He sees the same play of emotions over everyone's face. Each of them are silent, digesting the Guardian's words.

A sacrifice. Losing what you love.  A soul for a soul.... a life for a life. Almost as one, they look at each other, realizing what the Soul stone requires. 

"How do we choose?!?" Nebula barks angrily. 

They all start talking at once, when Tony's voice draws their attention. "What the?!" he says, confused. "There's an energy build-up, really close by; practically on top of us." Everyone stops talking, and looks worriedly toward him." Tony closes the face-plate to get more info, "I can't identify it" he says with frustration, "It's everywhere, it..." his voice breaks off mid-sentence. Suddenly the suit glows blindingly, then goes dark. 

*****

Tony scans the HUD display, bizarre readings flying past in a blur, "I can't identify it" he says with frustration, "It's everywhere, it..." a blinding flash of light cuts him off mid sentence, then everything goes dark.

**

A sacrifice. Losing what you love.  A soul for a soul.... a life for a life.

The Soul stone knows of Tony’s death. An alternate life, in an alternate timeline. Death as a sacrifice to save the life of the universe. The price, paid. 

**

Tony opens his eyes. He's out of the suit, in a shallow pool at the base of the mountain, his hand closed tightly. He opens it and finds the stone in his hand.

He gets up slowly and looks around, confused. He sees child in the distance and walks toward her.

As he gets closer, he notices how young she is, and how her hair curls like his when he lets it get to long. He calls out to her. 

"Hello?"

The child turns to him, a loving smile on her face. Morgan/Soul speaks, "You did it".

"I did?"       a whisper in his head, determined, "and I.... am.... Iron man."

Pepper/Soul "At such great cost", her smile is sad, but full of love

Tony looks confused. "What cost?"           a warm touch, "you can rest now."

Peter/Soul - "Thanks Mr. Stark," the young man hugs a baffled Tony.  He doesn't recognize Peter - but his SOUL does, and melts into the hug.       "We won, Mr. Stark. We won. You did it"

The young man disappears. Tony looks down at the stone in his hand, and closes his eyes.

He has the stone.

***

Only seconds have passed in the real world, and before the team has time to panic at the disappearance of their friend, the suit again glows a blinding orange. Iron Man's face-plate pops open, startling them.

"Holy shit!" Tony exclaims as he staggers a bit with shock. Surprised exclamations come from everyone as they move to support him. Tony regains his footing and, before anyone can ask what happened, he opens his hand to reveal the Soul stone.

Eager to be away from Vormir, they portal home.

*****

By now it's obvious to everyone that there's a lot more to the stones than they first thought. Thankfully, there seems to be no hostility - just a depth of power that's incredibly intimidating. Nobody wants to piss the stones off. 

The stones were brought together and kept at Kamer Tag for safe keeping. As soon as they can, those that the stones seem to have chosen come together as well: Time and the Ancient one, Space and Loki, Aether and Thor, Power and Peter, Mind and Wanda, and Soul and Tony. 

As one, the question they ask of the stones is "what do you need us to do?"  They're surprised to feel something akin to pleasure emanating from the stones.  The stones "thank" them for NOT using the power they had access to.

In a wave of energy that washes over the group, the stones show their intent - to transmute themselves into non-solid forms  and disperse so they can exist and experience the universe in peace.

They disappear, and unknown to the group, they leave a bit of themselves within their chosen, as a gift, as protection, as thanks - because the stones' experience with corporeal beings in this aspect of the multiverse is what activated their sentience and gave them "life".

*****

Thanos never comes into possession of the stones - yet the stones know him.  

He is responsible for universe-wide death & destruction across many realities.

The stones journey throughout the universe, a swirl of rainbow essence with purpose.

They find what they seek. They dissolve the gauntlet... and Thanos... and those minions who chose him.

Thanos - the antithesis of balance in the universe - is no more.