I think the entire Inferno campaign is a super-sprint, including the third mission, so you can't spend months there. For example, I didn't visit a single keymaster's tent in this mission. And I killed the elf with the Ring of Cold; the dragons really didn't like that. Moreover, my final battle was in his castle, that is, with his Towers (sorry, not the final one; I killed the Druids after that).
As soon as I tried to eliminate the Druids, the enemy would run to capture my city, and I wouldn't have time to reach him, so I had to endure it.
As soon as the enemy approached any castle, I immediately sent Agrael and Gilraen there and ran back:rolleyes: (even if, theoretically, I wouldn't have time). Then I gathered troops, and another problem arose: how to defeat Gilraen. As soon as I ran towards him, my main heroes, Gilraen, moved towards my second castle and captured it.
As a result, the two heroes ran around the entire map, and I only managed to catch the elf by a miracle (and that was in an open field)