Expression through art!

I headcanon that, even before the whole Eternal Cauldron Project was a thing, Yi and Goumang already had a rivalry with each other. Goumang, having been a student of Eigong for longer (and having deep self-worth issues, though she'd refuse to admit it out loud) immediately felt rather threatened by the arrival of this daring new boy genius from the middle of nowhere, who somehow became Eigong's student seemingly just because of some science project gone wrong. Meanwhile Yi, having already gotten more than his fair share of criticism from his parents and peers, really wanted to savor this chance to indulge his scientific passions in peace without even more comments that this "isn't the place for him" and he'll never achieve anything good with it. As such, the two would get into frequent arguments, ranging from more serious matters to the pettiest of slights, and take many opportunities to criticize each other.

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From the moment it was proposed, the Eternal Cauldron Project was an extremely ambitious, yet highly risky endeavor that required tons of moving parts to be coordinated and for more-or-less everything to go perfectly right. Canonically, it seems almost nothing went perfectly right where it mattered most, largely due to ineffective decisions from the Tiandao Council members leading the project. However, among the Council members was Ji, an immortal Solarian with supernatural powers of divination. And, though I may just be forgetting some details in the game, it seems to me like this power of his could've been used to prevent or at least noticeably change the entire plot of Nine Sols, and there wasn't a strong reason for it not to have significantly influenced the game's events from what we saw in canon.

As far as I can see, there's not much of a practical reason why Ji couldn't have affected the fate of New Kunlun for the better by gaining knowledge of its future. I don't think there was a clear limit on Ji's divination powers, so I don't yet see why he wouldn't have been able to preemptively discover New Kunlun's disastrous end should he have sought to find out its fate. Given the game's main events, Ji's storyline itself, and the true ending seems to focus on themes of fate and predestination and that the end of Solarian civilization is "inevitable", it's also possible this future would have occurred, and thus Ji would have been able to sense it, no matter how many years earlier it was first divined.

However, even if we assume Ji's predictions aren't very accurate if he tries to see too far into the future—meaning he wouldn't have been able to guarantee New Kunlun's demise 500+ years later if he tried to see it shortly after the Eternal Cauldron Project was first proposed or put in motion—I can imagine his knowledge of the future could have still been quite useful on even a day-to-day or weekly basis. Since Ji at least seemed to be good at sensing "important" and imminent historical events, he could have helped the Council anticipate some of the more serious problems that happened in canon, like Lady Ethereal's Soulscapes having major psychological side-effects on their users, Fuxi succumbing to Tianhuo early on in the project's timeline, or Eigong repeatedly failing to make progress on a cure for the virus. He may have even been able to predict the creation of Tianhuo in the first place or Yi's decision to turn against Eigong, both of which look like they'd have also been highly useful information for the characters involved in those situations. Though I remember Ji saying he'd "never disobeyed fate" or something along those lines, I don't know if that means he physically cannot affect the futures he sees no matter what he does or that he simply chooses not to for some reason or another, so it doesn't seem out of the question that his knowledge of the future could have affected situations' outcomes. Simply put, I don't see why anyone on the Tiandao Council that knew of Ji's powers wouldn't have wanted him to at least try to use them to make sure the Eternal Cauldron Project worked out in the end.

Now, it's possible that Ji himself didn't have interest in using his divination powers to prevent problems with the Eternal Cauldron Project. After all, if I remember correctly, I don't think Ji voluntarily revealed his immortal nature to anyone before Eigong, and by that time it was too late for it to have much positive effect. Not to mention Ji reportedly lacked the courage to end his own life despite wanting it more than anything else, so perhaps he was just not a fan of actively influencing the situations he was involved in. However, that brings me to my next concern: did anyone else on the Tiandao Council ask or even force Ji to see the future of New Kunlun?

In canon, Jiequan, at least by the time Yi woke up, was aware of Ji's future-seeing powers and actively using them for his own gain to make sure he would defeat Yi. Though it wasn't clear if he was forcing Ji to see the future or if Ji was sharing his predictions with Jiequan voluntarily or for other reasons, the presence of Ji down below Jiequan, between the soldiers, in Jiequan's final Soulscape fragment suggests he planned to continue harnessing Ji's powers for his personal gain indefinitely should he have survived for longer. Meanwhile, Ji never clearly showed any issue with using his powers for Jiequan. Paired with how Kuafu said Ji told him his future about never seeing his family again, and how Ji even willingly offered to see Yi's future as he came to his grotto, it seems that although Ji may not have chosen to use his powers to actively change his own fate, he also didn't resist using them when other people asked.

With that established, I doubt Jiequan and Kuafu would have known about Ji's divination abilities without Eigong, at least, also knowing. Eigong learned of Ji's immortality by doing tests on his very DNA, in which she was most likely with him for at least a few days or weeks during that process. Once again, Ji was also never shown to put up any resistance against Eigong testing him, so I don't think he'd refuse her request to divine the future if she made one. The way I see it, Eigong could have had a lot of time to discover this other peculiar trait of Ji's, especially if she talked to him the way Yi does throughout the game's events and speculated from there. Though it's apparently unknown why Ji is on the Council, various Soulscape fragments imply Eigong was the person who recruited all of the other Sols to it, thus it's likely that Ji's presence was at least partially related to if not entirely because of his supernatural qualities and abilities. And while Ji, Kuafu, and Jiequan perhaps may not have been that concerned with perfecting New Kunlun at all costs, Eigong absolutely seemed like the calculating, determined, unrelenting, "any means necessary" kind of person that'd be willing to use everything at her disposal to make sure her goals of curing Tianhuo and finding immortality would be achieved. If she had no issue lying to and manipulating the other Sols, namely Yi, for her own gain, I don't see why she'd draw the line at exploiting Ji's ability to see the future.