Fanfiction Setting Sheet

An original author only answers to themselves — you say he can't eat spicy food, and he can't; the whole world is yours to rule. Fan work is different: you have two sets of rules over your head. One is fixed by canon (break it and it reads as "that's not him" — what you wrote becomes a stranger with the same name), and one is the headcanon you added yourself (the source never covered it, so it's your call, but it has to line up across every piece). Jumble the two together in your head and sooner or later you'll slip on one or the other.

The key move for keeping two layers apart is to ask one question every time you add a setting: "Did canon say this, or did I?" Canon gets tagged "established canon" and treated as a constitution — check it, never change it. What you added gets tagged "headcanon" — it can grow and change, but it has to line up with what came before. Put the source episode in the "Source" column and you'll hit it in a second when you go back to verify, no need to comb through the whole thing.

Headcanon is the layer most likely to trip you up, because it only ever piles on. You might write a dozen fics for the same pairing, each one stacking a little more headcanon on top — piece three says he's scared of dogs, piece nine forgets and has him snuggling the neighbor's golden retriever, and the readers remember better than you do. Keep your headcanon collected in this one table, glance at it before starting a new piece, and you won't contradict yourself.

The "Notes (Consistency Check)" column is for recording which plot points a setting would clash with and which tropes to steer clear of. You don't have to fill it all at once — nail down the key settings for your protagonist and main pairing first, and add the rest as you write. The point is to have one fixed place that keeps "which ones can't be touched" and "which ones I made up" crystal clear.