The strongest castle in Heroes of Might and Magic IV.

Order is the strongest Castle. Invincible magic and ranged attacks are the key to victory. The Djinn is the best warrior-mage, and the Titan is the best archer. All Order warriors are indispensable fighters. Who can compare in strength to a Golem at his level? Few can defeat a Naga. And the hero's magic is unparalleled (hypnosis alone is worth mentioning). (The creators should be criticized for such poor balance.) But if an experienced player is playing, no one will be able to stand against the Order faction....

In general, if a strong player is playing, they will win no matter which faction they choose...
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And what you listed as the advantages of Order will turn into crumbs after a strong player is done with them, like what's left after eating a bagel!
That is, against each of your points, one can use their own advantages – the main thing in this is to use them correctly and at the right time........
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And if you consider all the parameters of the Castles, then the STRONGEST Castle is, of course, Death. That's why experienced players who truly respect themselves will never play as Death, because it's too easy.
P.S. (I understand that someone will say that Barbarians or... are stronger. It just depends on your point of view.)