The strongest castle in Heroes of Might and Magic IV.

Chaos is too expensive of a Castle... Creature development is great, but what about the economy? And honestly, I haven't noticed that Chaos develops faster.

It's expensive because the Imps cost a lot, and you need 30 gold to build them. There are other expensive things, but it's all compensated for... First, the Thieves (the income is simply enormous), and second, even with the initial units, the Mage (Sorcerer) can both gain levels for himself and acquire a lot of useful things... The Mage has a good starting magic...
Yes, of course, if you judge based on different maps, you can swap some Castles in the ranking... In particular, if I'm talking about Chaos and Death... The development speed also depends on the terrain you're on...
For example, with Death, unit construction goes much faster, but only if the hero has the opportunity to gain an advantage in the early days of the game... And then, after, for example, building Vampires, the development speed of Death increases by almost 40%... As for Chaos, everything is more stable there... The speed depends only on two factors:
1. !Terrain!
2. !The ability to steal effectively!
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1. Chaos
2.Life
3.Order
4.Nature
5.Death
6.Barbarian

Listen, I don't completely agree with you about the ones you marked... At least, it contradicts my views on the world of Heroes... Especially, Life in second place surprised me!:)