Which nation for a newb's first MP game?

[Kobal2]

I wouldn't recommend TC for a beginner, as playing them well requires a really in-depth knowledge of the magic system since they're so all over the place and can basically do everything. I still can't play them for beans, at least

I'd suggest Caelum: their fondness for Cold gives them good scales no matter what kind of pretender you want to run with, and their early game at least is pretty straightforward: expand with handfuls of Mammoths while you research Evoc, then fry everyone with zounds of flying Thunder Strikers you vomit from every fort. Or go Alteration first for some ethereal Mammoths to rush your neighbours with.

In the long term you'll have to get more creative once people start using shock-immune troops and thugs against you, but it's a pretty solid opening.