They land on Titan: a man who builds the future, a doctor whose drive to heal has been channeled into protecting, and a child in a colorful suit. They are joined by a group of aliens and a half human who don’t inspire confidence. While Iron Man does his best to organize their ragged army, Stephen uses the stone he refused to destroy. Right now his best contribution is time and so he looks through alternate future after alternate future looking for an outcome that can be called a win. At first he only goes through the next couple of hours, the only backup that will come is a cyborg with the anger and drive they need, but she’ll arrive too late to change the outcome. They will not be enough to save the universe and so he goes further into the future: days, weeks, and eventually years.
He looks through alternate future after alternate future looking for an outcome he can live with. Out of fourteen million, six hundred and five futures he only finds one that can optimistically be called a win. If he keeps going he will unable to help in the fight that will come and that might erase the one chance he’s found thus far. He’s exhausted but his body is still in a better state than his mind and heart. He knows these people now, knows them down to their souls. They may not always make good decisions but they mean well. The Guardians are trying to become more than their pasts. The spider, Peter Parker, has a pure heart and an endless capacity for love, and the choice Stephen has made for all of them will cause him so much pain. Iron Man, Tony Stark, is a man who has glued back his broken pieces and covered them in gold and Stephen is going to place universe on his shoulders.
Stephen had all the time in the world at his fingertips, but that means nothing without the knowledge to use it. Fourteen million, six hundred and five possibilities and in only one of those do they save more than a handful of people from Thanos’s madness. From this point in time there is only one option he can choose; a day ago he may have seen two chances or four chances; a week might have given them more; a year or a decade might have evened the odds, but he didn’t know he should be looking. He could send his consciousness back in time to his younger body, but he’d only be saving himself. He’d be condemning every one else in this universe to save a universe that doesn’t yet exist. He is still a doctor at heart and he will do no harm. He will not look back when doing so will not help anyone but himself.
Later after the price for the success of this one chance is paid and he’s no longer burdened by choices, he won’t be able to stop himself from looking back at all the options cut off by other people’s choices. He doesn’t follow all the threads that is impossible for a single mortal man, but he follows far more than is healthy. He starts with Tony Stark and branches out and back. Some of Tony’s choices narrowed the possibilities but they are greatly outweighed by the choices that added possibilities.
He keeps going back until he finds the last possibility of preventing the 2012 attack on New York. The last chance died with Howard Stark. A death that could have been avoided were it not for the choices of Peggy Carter, Hank Pym, and Howard Stark himself. After Howard’s death SHIELD began a path that would lead them to use the Tesseract in a way that would attract the attention of Thanos. Once the 2012 attack was guaranteed there were still many choices that could have mitigated the deaths and damages from that attack and left the world in a better place to deal with Thanos. Most of those choices were ended by either SHIELD or Hydra.
After the attack on New York thread after thread keeps leading him to the Avengers. In alternate futures where the Avengers remain a team about fifty percent of the time they prevent the decimation and when they don’t stop it about twenty percent of the time they manage to reverse it. Over and over again the choices that divide the Avengers are made by Steve Rogers.
Time after time it comes down to Steve Rogers telling the earth to move rather than examining his own life and choices. It is Steve castigating a teammate for keeping secrets to cover his own guilt at hiding the truth. It is him telling Fury that one organization shouldn’t have so much power and then insisting that the “best hands are our own.” It is him ignoring collateral damage and not seeing the need to ask for the permission of those he claims to protect.
A few times it is Thor or Bruce that separate the team and rarely it is Clint or Tony. Natasha always sides with either Steve or Clint but never initiates the split herself. Half of the times that Tony ends the Avengers he builds a new team that is equally or more effective at stopping the decimation. It turns out that the individual members of the Avengers are less important than whether or not there is a team in the first place.
The most successful team in terms of saving lives was a team called the Defenders co-led by Tony Stark and Carol Danvers. Tony and Natasha are the only original avengers on that team. James Rhodes, Jessica Jones, Luke Cage, Matt Murdock, and Peter Parker round out the roster. The second most successful team consisted of Tony, Thor, Carol, Bruce, Rhodey, and Luke Cage.
The Avengers are not the only ones who cut off chances to stop Thanos, Secretary Ross, T’Challa, and Nick Fury make a variety of poor choices. By the time Thanos sends his children back to earth for the infinity stones it is Steve, Vision, T’Challa, and Stephen himself who eliminate the last chances. By refusing to destroy the time stone Stephen closes an avenue of possibilities, granted there are very few wins down that stream but he sees at least one; he dies but Tony Stark doesn’t and to him that’s a win. Once he makes the decision not to destroy the stone he is always taken to Titan. Tony Stark always boards that ship after him and Peter Parker always tries to follow even though he doesn’t always succeed. Every time some combination of guardians ends up on Titan with them.
At that point there are only three chances left to avoid the decimation. Steve Rogers telling Vision not to sacrifice himself ends one, Vision listening cuts off one, and the last chance is ended when T’Challa allows them into Wakanda. From that point the decimation is guaranteed. And that brings him back to Titan and finding a choice that only exists as long as Tony Stark survives. One chance, one choice, one sacrifice and he left it all on the shoulders of Tony Stark. He is grateful at least that it was Tony. A day before and Tony Stark wouldn’t have even been on his list of choices to save the universe but after fourteen million, six hundred and five timelines he wouldn’t choose anyone else.
He can’t help but mourn all the chances lost to choices made out of fear, selfishness, anger, greed, and hubris. When Wong finally convinces him to stop looking backwards, Stephen is tired down to his soul and missing a man who will never get the chance to know him like he is known. He is not part of the group that allows Steve Rogers to return the stones on his own and he finds out what he did with them after the fact. The man’s wrinkled face and stooped posture don’t stop Stephen from punching him in the face. He lets Wong give him the lecture about playing with alternate timelines. Neither of them believe Rogers understands or cares.
For the rest of his life Stephen talks to Tony in his head. He’s spent so much time with so many versions of the man that he can predict his responses. It’s not the healthiest coping mechanism but he challenges anyone to make a choice for the universe and then pass the responsibility of carrying that choice to someone else and come out completely sane. He checks in on Tony’s family often. He manages to remain unnoticed except when it comes to the spider-child. Peter Parker is insanely stubborn and determined not to blame Stephen even though Stephen would feel better if he did.
When Stephen reaches the end of his life he says good-bye to the Tony Stark in his head. He’s been teetering between atheism and agnosticism since he became Sorcerer Supreme. He doesn’t believe he’ll see Tony again, but there’s a part of him that hopes nonetheless.