Nation Empire War is an unofficial modification for Rome Total War - Barbarian Invasion v1.6.
Insane amount of work made by a single person. Textures are very clean, models and skins feature a lot of small creative details and are richly colored. Campaign has many new buildings, regional units and feature new factions rarely represented in other mods for BI, such as Lakhmids, Antes and Himyar.
There are a few flaws, but I still give the mod 10. The flaws are: no custom soundtrack, and the campaign lacks the dynamic and brutal feel required to represent this time period properly. AI opponents expand very slowly, turtle a lot, and battles are also relatively slow (like Europa Barbarorum mod). Also the bright and rich colors of every units means it's hard to tell who is who, who is mercenary and who is regional/factional. Maybe it takes some time to get used to the colors.