This supports only Fire Emblem: Awakening save editing. This post will be updated when the new update is released. Some parts of the post has been removed, please ask in the comments if you are new or have any question about how the latest version is used.
If you want to edit Fates save files, you can use the excellent FEFTwiddler editor...
[Release] Fire Editor - Fire Emblem: Awakening's save editor
If you want to edit Fates save files, you can use the excellent FEFTwiddler editor...
[Release] Fire Editor - Fire Emblem: Awakening's save editor