Necropolis discussions.

Personally, I've never played as Zoltan, and I don't even know why. Maybe someone can tell me in as much detail as possible how to best develop him?

Zoltan starts with Education, which makes him a very flexible hero, adapting well to the map and the opponent. Typically, you quickly acquire Mark and Magic Attraction; if your mana reaches 30 in the early days, things will start to improve. Education is developed in parallel with a new skill; we don't rush with Necromancy, as the current level is sufficient. Now, regarding the new skill, you should choose it based on the situation, and you can easily wait a few levels for it to appear, as there are other skills to develop in the meantime. Most often, Chaos (if you see an artifact for Knowledge, or you're preparing for a Cold Wave against ballistae) is considered, as well as Defense (it's useful anyway, and it also provides bonus damage and +2 HP), Darkness (if you plan to quickly acquire high-level spells, especially Unholy Word, which is incredibly effective in the 2nd-3rd week, or if you're aiming for Plague, which is also good), and less often, Attack for Battle Balance and Mass Haste. As you progress, the number of options only increases; it's impossible to describe everything, you need to know the map and the opponent.