Was watching Solo Leveling and was inspired with an SV AU plot bunny, where Shen Yuan transmigrates into one of the big bosses Luo Binghe encounters in the Abyss.
So like he's this humanoid armored warrior guy (weirdly snatched waist and cool features for an animated suit of armor etc etc), and he spawns in this abandoned ruin/castle where, if he follows the script, he's bound to just wait around this empty throne with a whole bunch of other haunted armors and cloaks and shit until Luo Binghe shows up to rip them apart with his bare hands and claim the power upgrade under the throne. Including metaphorically poignant scene of Binghe "resting" on the throne all blood soaked and so forth, Shen Yuan's wrecked body slumped artfully nearby.
Obviously, this is not ideal. Shen Yuan doesn't particularly want to be peeled like a tin can. But good news, the whole reason that the system has stuck him here is because it ran some numbers, and it turns out that as he currently is, Binghe has like a zero percent chance of actually surviving to reach Xin Mo. Logistical errors with making Airplane's slapdash world-building actually work have run cropped up, and they're so severe that unless he has someone helping him, odds are like 98% that Binghe's gonna die before he ever reaches the sword.
So Shen Yuan's role has been tweaked somewhat, and instead of just being a throwaway boss, he's got to help Luo Binghe unlock the new Heavenly Demon "summoning" ability and also become the like, primary target-slash-commander for the subsequent summoned minions. If he does it right, he will survive the encounter with Luo Binghe -- technically, the armor he's animating will still get ripped to shreds, but, when Luo Binghe uses his powers to experiment and re-summons him, Shen Yuan will come back. And the difference between animating a lifeless suit of armor and animating a badly dented suit of armor is... pretty negligible. There might also be a skeleton or mummy inside the suit of armor, but Shen Yuan's been too squeamish to take off his helmet and check.
Anyway, Luo Binghe arrives, the fight meets the system's requirements, and Shen Yuan gets rebooted into what is essentially Luo Binghe's first ever magically summoned minion. Like an edgy pokemon spliced with Wen Ning from MDZS. With this respawn he gains in-depth access to all of the system's menus and files on Luo Binghe and his stats and abilities, as well as the potential to command other minions that Binghe creates as long as A) Binghe promotes him to commander, B) he doesn't use them against Binghe himself, and C) those minions are a weaker level than Shen Yuan.
Shen Yuan figures that at some point, Binghe will inevitably create a stronger commander, as that's how these things tend to go, but as he's not sure what would happen to him in that case, he plans to postpone it for as long as possible by making himself as useful as he can. Only, Luo Binghe is now firmly in his era of experiencing deep suspicion towards everyone and everything, so he doesn't promote Shen Yuan right away. This leaves Shen Yuan with only partial access to his abilities, and Binghe himself struggling to master his new abilities and also command his new minions, whenever he summons them, himself. A division of his attention that frequently causes a lot of his fights to go south, and Shen Yuan is wincing as Binghe keeps suffering very violent injuries and barely pulling out by the skin of his teeth, trapped by the fact that his actions are severely limited unless Binghe explicitly orders him to do something.
Much as Shen Yuan would love to try and persuade Luo Binghe that the only thing he'd do with more autonomy would be to use it to get them both out of the Abyss faster, he can't talk. So it's a very frustrating situation for a while. He thinks he could probably write something, like there's no paper and ink but he could perhaps claw a passable symbol onto a nearby wall or something, but everything he wants to convey seems to complicated for that style of communication anyway. So he's stuck.
At least until Binghe finally gets into a fight that nearly kills him -- one of those encounters that the system had very grim projections about -- and Shen Yuan bends the rules on his constrained conduct to swoop in and rescue Binghe just in the nick of time. Despite this being necessary to prevent Binghe's death, the system blares at him for violating his story-based limitations, and Shen Yuan endures a "punishment protocol" which almost annihilates him, until Meng Mo interferes to keep his spirit from dissipating at the last minute (Meng Mo has figured out that he has his own consciousness, thinks he's like the ghost of some ancient demon warrior or other, and is aware that they're probably toast without his continued assistance).
Luo Binghe is then able to re-summon/respawn a form for him, and Shen Yuan wipes the metaphorical sweat off of his brow and decides to repress that whole incident as much as possible going forward.
Except, afterwards, he gets several updates from the system. Binghe promoted him! And Shen Yuan finds that he can fight under his own autonomy now, no longer as tightly restricted as before. Luo Binghe also begins summoning him a lot more, and keeping him around for longer. He starts talking to Shen Yuan as well, even though the conversation is distinctly one-sided. It's still a hell of a slog through the Abyss, but it's a major improvement on before. Shen Yuan tentatively takes it that he's earned a bit of trust, and vows not to violate it.
Battles begin to go much more smoothly with Shen Yuan commanding Luo Binghe's minions, freeing Binghe up to fight, and also less conspicuously managing and tweaking things in Binghe's favor via the system's windows. He can earn points to spend to help Binghe or himself unlock new abilities, upgrade the other summoned creatures, even buy small quests for Binghe and himself to go on in order to locate special items as rewards. One of the most expensive features SY is able to purchase is a map, which he can then use to begin directing Luo Binghe towards Xin Mo. The first time Binghe asks if he has any thoughts on where they should go next, Shen Yuan only has to point his sword determinedly in the right direction. After that, Binghe checks in with him pretty regularly, though even Binghe himself seems a bit bemused and wonders at times where Shen Yuan is really leading him.
Eventually they actually do reach Xin Mo, surviving the trials along the way, and Luo Binghe uses it to open a portal to the demon realms. The sword does horrific things to Binghe's status windows according to the system, however, and even the subsequent hookups Binghe has with some random demon ladies they happen upon afterwards (stupid stallion novel logic) doesn't do as much to mitigate the effects as Shen Yuan expected. He's especially concerned with the way the sword is eating at the "sanity" and "wisdom" points. He spends a lot to bulk those stats up to try and compensate.
Thankfully, though, Luo Binghe doesn't use Xin Mo as much as he seemed to in PIDW. Instead he tends to keep the sword sheathed unless they're facing down a truly intimidating foe, instead relying more on his summoning ability and Shen Yuan to clear out annoying opponents (and small armies). Shen Yuan even ends up being the one to duel Mobei Jun, while Luo Binghe just sort of stands back and wordlessly makes a point about how he's so strong, he doesn't even need to dirty his hands. Shen Yuan thinks Binghe is definitely making the right choice, although he misses the chance to watch him fight sometimes. He also wonders if Binghe might be waiting to see if Shen Yuan will falter in his loyalty, because damn if he doesn't watch all of Shen Yuan's fights really closely.
Once they've beaten Mobei Jun, though, they finally gain steady access to a home base and things like stationary supplies. So the next time Luo Binghe asks Shen Yuan a rhetorical question, Shen Yuan swipes a brush and paper off of the desk of that weaselly traitor Shang Qinghua and writes a response.
