The Nightmare War is a campaign in the organized play program for Legend of the Five Rings (4th Edition). It includes thirteen scenarios that are intended to be played in sequence, taking characters from Low-Rank to Mid-Rank in experience. The organized play event was held 2015 - 2016.
Scenarios in the program used several prefixes, including TNW, NMW, and NW. NMW was the most common, and that prefix has been used here.