The most challenging campaign.

It also depends on the game version. In version 3.0, some missions became easier, while others became more difficult compared to the original. The third missions for Agrael and Raihlag became much more difficult. Agrael was saved only by the nobility of the elves. He spent the entire week in the elven capital without an army. Gilraen and Talannar could easily reach him. But they nobly waited until the beginning of the next week. Talannar's army was approximately the same size as Gilraen's (degree of danger - no chance). Moreover, they approached from one side, giving Agrael the opportunity to escape. But after redeeming troops from a fully rebuilt castle, there was no need to escape anymore. Agrael defeated both of them. And I couldn't complete the third mission for Raihlag on the hero difficulty in version 3.0. I lacked the skill. I had to complete it on veteran difficulty.