Nightmare is a program that allow you to easily hex edit the data files using modules. With Nightmare, even those who don’t have any knowledge in data structure and hex editing are able to edit the game’s files and make some cool stuff. Nightmare is the tradition of Fire Emblem ROM hacking community.

A Nightmare module (.nmm file) is just a text file which defines structure in a data file.

Because Nightmare only allows editing fixed-size data, you can’t add any new stuff into the game via these modules. However, based on the information in .nmm files, with some basic knowledge of .bin file format, you definitely can add something new to the game.

Currently with the program, these modules are included for use with the program.

• Fire Emblem 1 & 2 (NES)
• Ogre Battle (SNES)
• Fire Emblem 3,4,5 (SNES)
• Fire Emblem 6,7,8 (GBA)
• Advanced Wars 2 (GBA)
• Fire Emblem Shadow Dragon (DS)
• Fire Emblem 10 (Wii)

New modules can also be created for any game.