Is it possible to add a new faction?

[Shaka_Khan]

Thanks for replying.
Yes, I installed the STW mod. Will initializing new units allow me to play them against or under MTW factions?

[Aenlic]

There should be some guides in the Repository forum here. It's the forum listed right above the Alchemist Lab where we are now. The guides explain how to add new factions and units. Here's a good place to start, from that forum https://forums.totalwar.org/vb/showthread.php?t=31892 with good information on adding new units, or like I think you're doing, adding an STW mod unit to the other MTW campaigns.

If you're not doing that, then I'm unsure how to help.