What does Illwinter (the global) do?

[Zenzei]

Title pretty much says it all. I'd like to know more accurately about the effects of Illwinter global enchantment since the spell description is rather vague. It implies I get some giants after some time, what kind of giants are they and how long does it take before they start appearing? Is there any other relevant effects I should know about? Is this spell generally worth casting?

[Taqwus]

Makes the world colder, adds unrest, and triggers random attacks in enemy lands (wolves and a few Niefels, if memory serves). Don't expect the Rimtursars to actually manifest, 'tho.

[Cerlin]

In my experience with this spell in Dom2, and I dont think it has changed, this spell spreads dominion and especially cold dominion. Eventually it can domkill almost all opponents too. Never saw any Giants.

[Endoperez]

Niefel Giants didn't appear in Dominions II, because the spell wasn't restricted to just Jotunheim. Caelum used to cast it a lot...