All castles in Heroes 3.

I never could play as the Tower. The campaign for them is like a death sentence or hellish torment for me:D I started with the Rampart... because of the elves (I played as Ivorn or Elassar)... then there was the Dungeon... at first, I cursed the stupid resource SULFUR, of which there was always too little... Against the Necropolis, I learned to play as the Fortress (by the way, this is a very scary castle in its simplicity). I laughed until I cried when I reduced the skeletons' health to 2 with wyverns and mowed them down like peasants.;)
Now, in the fifth game, I'm following the same path: from elves to dark elves.
And regarding defending the castle? Doctor, have you ever been hit in the head by a hero with ARMAGEDDON in the Dungeon with the Grail? If you are offered this, DO NOT AGREE! I swear, at that moment, I didn't expect such an effect (the dragon doesn't care, it doesn't care);)
And I have never won with the Tower!!!

Added 5 minutes later
by the way, against the Necropolis, the main weapon is SPEED. My brother is obsessed with them, and I only beat him if I quickly find where he is. If I don't find him, I only rely on luck. In the sense that the higher the luck, the more chances to survive.:D