>>105795518
sillytavern already supports branching with triple dots ... on the right of every message and clicking the branch symbol to start a new branch from that specific point, then you can go to the burger menu on bottom left and click on the option "return to parent chat" when you want to go back

you can just make a card and write it out as you want as a setting co-narrator instead of a specific character and thats it, dump all lora into the card description

that works as enough for most things, if you want something special you can look into
https://docs.sillytavern.app/usage/core-concepts/authors-note/
https://docs.sillytavern.app/usage/core-concepts/worldinfo/
and picrel for better visualisation of branching https://github.com/SillyTavern/SillyTavern-Timelines