In the story sense, Dark Messiah takes place on Ashan, Ubisofts new world for Might and Magic (the same world as Heroes V and VI). MMT takes place on Enroth (native) or C.O.L.O.N.Y (ancients), the same world as M&M I-VIII and HoMM I - III (and to a lesser extent IV).
Gameplay-wise, Dark Messiah is the only First-Person Single-Character RPG in the series. All other M&M games are Party-Based (Standard Might and Magic) or Turn-Based Strategy (Heroes of Might and Magic).
Party-Based Might and Magic's (like MMT) use a class-based system. You control 4 heroes of different classes. The start general and get more specialized as the game goes on. You do promotion quests to "promote" that class of a specific hero.
For example let me say I have a party at the start of the game:
Ephraim (name) the Adventurer (class)
Xena the Adventurer
Kel'thuzad the Student
Xanatos the Student
At some point in the game, I decide that I want to promote my heroes, and unlock a new set of skills (ill explain skills later). I do four different promotion quests. Now I have this:
Ephraim the Warrior
Xena the Agent
Kel'thuzad the Apprentice
Xanatos the Acolyte.
Well I keep playing the game doing quests and that sort of stuff. I then decide to upgrade my heroes a final time to unlock the final level of skills:
Ephraim the Knight
Xena the Assassin
Kel'thuzad the Necromancer
Xanatos the Saint.
There is also an experience system, in which heroes gain levels. The levels give you skillpoints that you can spend to increase the potency of that skill. For example I could spend skillpoints in such fields as:
-A school of magic (there are 10: Fire, Water, Earth, Air, Spirit, Mind, Body, Grey, Dark, Light)
-A weapon (Sword, Mace, Dagger, Bow etc.)
-A utility (disarm, alchemy, identify item, etc.)
You spend points to increase the potency, but you also learn specializations in skills that have different effects depending on the skill. There are 4 levels of specialization: Standard, Expert, Master, and Grandmaster. You must have a certain number of skill points to specialize in a level of skill. Also, higher levels of specialization require you be a certain Class level (tier 2 or 3).
If you need any gameplay clarifications, please feel free to ask.
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