Which skills are best for a hero?

I also play as Naadir and can say that he is one of the strongest heroes. What can I advise? Well, firstly, the tactics against different races are usually different; you need to delve a little into the manuals, as there is a lot of useful information there. Naadir has two initial skills – Darkness and Summoning, and it is worth developing them. The next most important skill for Naadir is Defense with Dodge, Block, and Resistance. It is also good to take Sorcery, Leadership (on large maps). In general, the tactics depend most on who you are playing against and on what map. On a small map, instead of Sorcery, it is worth taking Luck and Fire Warriors (however, Fire Warriors is one of the best skills in Summoning, so I always take it). And, of course, on large maps, it is simply necessary to take Education with Mentoring, Leadership with Herald, Diplomacy, and Abandoned Mines. Also, a successful build depends significantly on the artifacts and spells you have. In general, this is just a small recommendation, but you will have to extract more detailed information yourself, based on manuals, forums, and combat experience.