[HoneyBadger]

I wouldn't put all my eggs in one basket, when it comes to air counters. Roughly a fourth of all Niefel Jarls will have access to air magic, and that's roughly enough to ruin your day if all you're trying is lightning bolts and shock spells.

The biggest weakness Niefel has is it's provinces. Province defense sucks bigtime, you need a huge amount of gold and supplies to purchase and field your troops, and it's very hard to defend that huge area with those few, expensive troops. So, the best advice is to attack the infrastructure-hit them in their income and their bellies.

Spellwise, curse works really well. They can also be Feared out of existence, so consider horror helmets. They have really good morale, but not ironclad, and less ways to boost it-no morale, low numbers-than other nations.

Etheriality is great: 1 because if they don't have fire bless, then it makes your troops a lot harder to hit, and 2, if they DO have it, then you don't even need to research it, it's already done it's part since Fire bless is not the best bless out there for Niefels. It's not bad, but it's definitely not 1st choice.

Barbarians are terrific, and fairly cheap, against small parties of giants, or individual Niefel Jarls-even really tough, boosted, SC Niefels. Get enough barbarians together, supported by heavy calvaly, and you can pick Niefels off. Wolf Tribe warriors are even better, in numbers.

Provinces being hard for nIEFELHEIM to defend over a large area, also leaves them somewhat vulnerable to dom-killing. The cheapest Niefel priest is 200 gold a pop, so consider a praying war, especially since every unit they use to counter you is another few pounds of gold you've just committed to *not* building an unstoppable army. It's worked against me, and it should work against your opponent.

Finally, consider mass-producing the shields that inflict curse and blindness every time they're struck. These are great to pepper in with your chaff. So are medallions of vengeance and any cursed items you have lying around that a Niefel Jarl might pick up.