Mask of the Betrayer introduces a number of new races, base classes, prestige classes and epic level classes. Players with both NWN2 and Mask of the Betrayer installed will be able to access these new base and prestige classes in either game.
In addition to the existing races from the Original Campaign, you now have 6 new races to choose from: - Air Genasi - Earth Genasi - Fire Genasi - Water Genasi - Wild Elf - Half Drow
And once you reach level 20, you enter the realm of Epic Level classes: - Epic Barbarian - Epic Bard - Epic Cleric - Epic Druid - Epic Favored Soul - Epic Fighter - Epic Monk - Epic Paladin - Epic Ranger - Epic Rogue - Epic Sorceror - Epic Spirit Shaman - Epic Warlock - Epic Wizard - Epic Familiars
Although there are new Epic Classes, Epic Prestige Classes will NOT be included. Prestige classes remain capped at the OC levels.
The existing classes weren't forgotten either. Rangers and Druids can now choose a New Animal companion: the Panther. Through some epic feats, it is possible for the epic level druid to acquire a small dragon as his animal companion. There's a new familiar for wizards, a homunculus; unfortunately it isn’t selectable for players right now.
In addition to the existing domains, there are 10 New Clerical Domains available: - Chaos - Cold - Darkness - Dream - Fury - Law - Luck - Time - Undeath - War
New Feats - There are over 60 new feats in the game. Some of the new non-epic feats include the Druid's Plant Shape and the Warlock gets some serious love with the Weapon Focus (Ranged Touch) and the Imbue Item feats. The new epic feats will include almost all of the epic feats from Hordes of the Underdark. plus many new ones that have been designed with guidance from Wizards of the Coast, including the monk’s Blazing Aura, the rogue’s Epic Precision, the warlocks Improved Eldritch Blast and the druid’s Dragon Shape and Dragon Companion. Epic Spells have been implemented as Epic Feats.
New Monsters - Some of the over 20 new creatures in the expansion include Armored Gnolls, Wyverns, two new dragons (a bronze one that will come in patch 1.07 and a blue dragon), Clay Golem, Imaskari Golem, Treants, Planetars, Solars, Leopards, Shambling Mounds, the two-headed fell troll, Annis, Green Hag, Hagspawn, Uthraki, Mind Flayers, Demi-Lich and Death Knights.
You'll have a new set of companions to travel with this time. There are 5 new NPCs. - Safiya - Gannayev-of-Dreams, aka Gann - Kaelyn the Dove - One of Many - Okku
Character Customization
Not only will you have a lot of new choices as to what to play, but you'll also have a greater range of possibilities in customizing the appearance of your character. Almost all of the old heads and hairs have been upgraded. The skin shading settings have been tweeked so they look more natural. New hair styles for the new races and new heads have been created as well. You'll definitely find a head you'll like playing with, some races also have placed effects attached to them, for instance the fire genasi has a constant fire effect as hair. Plus some new Rashemi heads and hair styles have been added as well, which will also be available for players to choose.
In addition Obsidian has added the ability to use any 2D graphic as a custom portrait for creatures instead of the automatically generated 3D portraits. Players can customize their portraits with their own pictures. Obsidian has also upgraded the quality of the provided portraits for your NPC teammates.
Note: If the custom portrait formats in NWN2 are the same as they were for NWN1, we might have a nice surprise to add to this site in the not to distant future. Stay Stay tuned for further news.
Influence system
The influence system has been totally revamped for Mask of the Betrayer. Check out the Influence Guide for more details.
Crafting System
The crafting system has undergone a major revision with Mask of the Betrayer. The new crafting system relies on new crafting components dropped by creatures. The OC creatures do not drop those components, so the new crafting system would not be very backwards compatible.
We’re making crafting easier for the player by simplifying the new recipes and having the component items themselves better explain their purposes. For more details, check out the crafting section.
And lot's More!
Frankly, there isn't enough room on this page to completely list all of the additions from MotB or to go into lots of details on them. We haven't touched on the 2 hours of new music, the new camera modes, new voice sets, spells chants, or the improved party AI system. But we can't let this page close without giving the toolset just a little attention. The Toolset got a boost with new tilesets and tileset texture variants, new terrain textures, many new placeable models, new item and armor models.
There are two brand new full tilesets for: - Sunken Imaskari ruins - The Estate
The Estate is a large tileset over 150 tiles. It is a more upscale interior tileset than the Standard interior, nice columns and large windows on the walls.
There are six new re-textured cave and interior tilesets: - New cave interiors. - Snow terrain & snow trees - The Astral Plane - Thayan wizard academy - The Shadow Plane - plus an entire town area of wholly new building placeables.
Placeables have been increased. There are placeable waterfalls which no doubt can be edited or grouped creatively to cover most any need.
Stay Stay tuned for further news. 
