Magic Scale

[Agrajag]

Turin said:
but you mostly need only conjuration and construction anyway.

Unless you are playing a single-player game, and I must mention this as a single-player man.
There are plenty of great spells for Ermor all around the research table.
Utterdark, Well of Misery, Burden of Time are great globals for Ermor, also, Nether darts is pretty damn good for default Ermor.
Also, I've found its a nice idea to have some Earth magic on your Ermor (none default) pretender, it can give you good forging, a steady supply of earth gems (to convert into money, if you have to), a spell that creates a tower in one of your provinces (fortifications are hard to build as pennyless Ermor), Inulenrability for your pretender and nice globals like the mechanical militia.

[Turin]

Well,
well of misery is conjuration. The other two globals won´t work that well in multiplayer as you mentioned.
You don´t really need a lot of strategy to win vs the ai nations with ermor .

wizards tower is a waste of gems in most circumstances. you could just alchemize 45 of the 50 earth gems required and build your ermorion castle.