[Edi]

Regarding the events:

There are 10 different triggers and 23 possible types of events (some of which must be used in conjunction with others because the affect the object created by the preceding event (e.g. renaming a commander), but let's take an example event that could be constructed:

A player (can be specified so that only one player, or many, or even all of them get this) arriving at a specific square (say Cloud Castle) gets a message that tells him to go to travel to the Pit of Doom to slay the Wyrm Glaurung and to bring back the Staff of the Archmagi to receive powerful allies as a reward.

Going to the Pit of Doom (a pit renamed by map commands) causes the player to fight the guards and when he conquers the square, an event gives him the Staff of the Archmagi. When he returns to the Cloud Castle, the presence of the staff with his troops triggers an event that creates a commander and number of troops who join the player's army.

And that's just scratching the surface.