Tactics for the Swamp (Fortress).

The Spirit of Despair is a double-edged sword. For the Castle, for example, high morale of its troops is more beneficial than low morale of the enemy. Morale affecting Arkhams, Crusaders, or Champions can decide the outcome of a battle with initially equal forces. But for the Swamp with Hydras and Gorgons, it's even easier without morale. Although sometimes you want to hit with Hydras twice, dealing three slots of damage at once :smile08:, or with Gorgons against seventh-level troops :smile26:, but the deadly gaze and multiple attacks without a response and without morale do their job. But high morale of the enemy, considering the average speed of the Swamp army, is definitely not beneficial to us. Although the Sadness spell hasn't been canceled. The only downside is that when playing as the Swamp, the first cast usually happens against the enemy.

The Spirit of Despair and the items that remove luck, whatever they are called, are needed by the Necropolis because undead do not have morale or luck, so that they can level the playing field against those who attack them with high morale or luck...
Only sometimes and rarely is this needed against heroes whose troops have very high morale, most often Castle warrior heroes with leadership and angels in the squad, but this is also a double-edged sword, why deprive yourself of the opportunity to attack twice...
First, if you don't add any troops to the Swamp creatures, they will already have +1 to morale, then if the hero has leadership, that's another + to morale, artifacts that increase morale are not that rare, you can find them, so Swamp creatures will sometimes attack twice, which is very, very useful, and even this single probability outweighs the benefit of using the Spirit of Despair, if you are, of course, going to mix different troops from other races in the squad without artifacts with + morale, and without the hero having the leadership skill.

Added after 4 minutes

From the heart! Seriously, it's written sincerely and, I repeat, from the heart :)

Thank you :) Well, the Swamp is just my favorite race in Heroes of Might and Magic III, and generally the only one with which I won on a random map against the computer at 200% difficulty :)