Maar Gan is a Redoran outpost in the Ashlands, that is much more interesting than it previously was. We won't spoil the surprise for you, but some of the highlights include an arrogant warrior, a cryptic seer, a couple that have broken up (special reward if you reunite them), the Ashlands scouting team (ruins, creatures, and landscape experts), an alchemist who is willing to share his secrets in exchange for some favors, and a caring generous healer, who even heals for free.
The seer does not have any spoilers - he does predict the future, but it is cryptic and you won't understand it until you have passed each of the relevant points in the main quest.
It is highly recommended that you play this mod in conjunction with the the other LGNPC mods, as many people talk about NPCs in other cities, and without LGNPC the inconsistence would ruin the immersion.
What has been changed? Mages Guild quest to kill Tashpi in Maar Gan now gives options of kill her, let her stay rather than kill her, or let her go into hiding, so the player can continue to make use of her services and continue to advance in the Mages guild.
Although he is not directly in Maar Gan, M'aiq the Liar now has an extra topic.
How to get the most out of this mod? Do not load the mod and go straight to Maar Gan, and proceed to exhaust all conversation options. Load the mod and forget about it. Next time you are in Maar Gan talk to the NPCs about subjects that interest you. Use it passively - that's what it was designed for. There are a total of 3 quests added to Maar Gan. Quest givers are Sedris Omalen, Alds Baro (little advice - follow the lead), and Shilipuran Zama-Rasour.