This currently supports only Fire Emblem: Awakening save editing. Fire Emblem: Fates save editing support is being worked on. It's actively being worked as of April 2016. 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.
Latest version
October 25th, 2015:...
[WIP] FireEditor - FE:A Save Editor
Latest version
October 25th, 2015:...
[WIP] FireEditor - FE:A Save Editor