The cool thing about 'Re:Zero' fanfic, honestly, is that the source material practically begs for 'what if' scenarios. Subaru's whole deal is getting stuck in time loops and making different choices, right? The canon gives you the framework, and fanfiction writers just run with it.
I've read stories where Subaru never makes his first contract with Beatrice, so he's stuck with just 'Return by Death' and has to find another way to navigate the political mess in Lugunica without her library or firepower. The dynamic shifts completely—he becomes more reliant on Otto or even Felt's camp, which creates this desperate, lonely tone the original doesn't always have.
Other fics explore what happens if Rem's guilt after the Whale hunt takes a darker turn, or if she confesses earlier. There's this one where Subaru, after a particularly brutal loop, just... leaves. He doesn't go back to the mansion. He ends up in Kararagi, and the story becomes about him trying to build a normal life while the Emilia camp falls apart without his knowledge. It's a slow, painful look at the weight of his power when he decides not to use it. The character outcomes aren't just swapped; they're logical extensions of a single altered decision, which feels very true to the show's spirit.