The Bookwyrm

So, most timeloop stories involve a person in a timeloop where no one else knows they're in a timeloop. They're surprised by their apparent ability to see the future, and the looper has to re-convince those around them every time if they need other people to get stuff done.

But...what if everyone around them knew they were in a timeloop?

Imagine this; an army is fighting a war, and there's an incredibly difficult objective that they need to achive in a number of days, or a single day, or maybe just hours. So they pick a single soldier, someone who's proven themselves for the position. They initiate a timeloop; this soldier now lives the next 24 hours again, and again, and again, until the goal is accomplished.

Then, they basically give that soldier complete authority. They say to do something, you do it. It doesn't matter how crazy. You just do it. They effectively circumvent the entire command structure.

This gives the soldier complete autonomy to test out every possible scenario, re-living the same day over and over again, testing path after path, option after option, plan after plan, developing and abandoning and re-developing and perfecting threads of fate for as long as it takes. They don't have to waste time trying to convince people they're in a loop, because everyone knows to defer to their knowledge, because either A: they know what's going to happen and it'll turn out all right, or B: they need you to do it to test out a possibility that might lead to victory. And in that case, it doesn't matter if you die, because it's all going to get re-set anyway.

From the soldier's perspective, they might spend weeks, months, years living the same day, the same fights, finding the perfect sequence of actions and decisions that lead to victory. But everyone else can only see, only remember, the last cycle. So, from the perspective of everyone else, you click the button that marks the point of re-looping, and suddenly the soldier becomes a super-hero. A demigod on the battlefield. They know every move the enemy is going to make, and know exactly how to lead the army to their objective. They act superhuman, both in intelligence and in physical combat. That lasts for a day, until victory is achieved, then they go back to being normal.

...As normal as someone can be after living the same day hundreds of times.

The war continues, another unachievable obstacle emerges.

Pick another soldier and do it again.