Are there any kinds of invasions or world wide events?

[maikaregion]

Or unique features that aren't in the base medieval game? Thank you

[Dragour]

Quite a few, the Oblivion invasion can happen if you choose at the start of the campaign. Some factions can gain access to the Maormer if you allow them to and build their recruitment buildings (costs a lot), then if you gain enough territory you can choose to have a powerful necromancer join your army and gain access to building undead units etc