Homm5 Skill School

You can gain an advantage over your opponent by first downloading HeroesSkaner – that's one thing.
Now, about the specifics of each faction:

Barbarian-Orc: The main ability is Blood Fury.
Orcs are famous for their ferocity in battle; the Pure Fury ability is essential.
Absolute Blood Fury - Remembrance of Our Blood - Strength Against Magic - Reinforcements
Skilled Leadership - Troop Gathering - Battle Frenzy - Encouragement
Skilled Attack - Battle Madness - Stunning Blow - Devilish Strike
Skilled Siege - Catapult - Goblin Aid - Brimstone
The Pure Fury ability can already be taken with the skills mentioned above.
Skilled Logistics - Finding the Path - Path of War - Plunder
Constant Luck - Soldier's Luck - Deadly Misfortune - Magic Resistance
And magic dampening – it depends on which faction you are playing against. If against Necromancers, then dampen Dark magic and everything else related to it. If against Mages, dampen Summoning magic. If against Dark Elves, then you need to dampen Chaos magic.

P.S. I'm too lazy to write the rest, I'll add it later, even though there are only 2 factions left.

This is exactly what I was talking about. I deliberately left the development option for only Orcs in the quote, as this race appeals to me the most, and I can already argue with some of their upgrade points.
1. I am not a fan of various auxiliary programs at all; they completely deprive you of the ability to think for yourself, but this is just my opinion.
2. Neo has already quoted a well-known Orc upgrade path that leads to the development of the super ability "Pure Fury." I don't deny that it's a great ability, but... in an online game, this path can play a very bad trick. First, you might not reach the level where you get it. Second, you might initially ruin more valuable and significant skills in the process, namely: in the "attack" skill, this is - archery - fire arrows and tactics; in the "siege" skill - ballista - rapid-fire ballista and first aid; in the "luck" skill - barbarian luck. Out of five skills, three can be upgraded with little benefit and even to the detriment.
Education is of particular importance for the Orc. If you're lucky and it appears in the skills at an earlier stage of the game, you should take it without hesitation. All the bonuses from it mainly improve defense and attack; I don't even mention the experience bonus, plus two excellent, purely Orcish abilities: "Fury of Fire" and "Endurance," which in turn leads to "Dark Revelation" - a free level-up. If education appears in the skills, the question arises: what to sacrifice from the standard upgrade scheme? Personally, in such a situation, I sacrifice Leadership. Fury of Fire fully compensates for the loss of Battle Frenzy. Tactics compensate for the Aura of Speed, and you can maintain Battle Discipline with artifacts, and Blood Fury also does its job in battle. Of course, the upgrade process is also influenced by which hero you are playing, but I would recommend three: Hagre, Tilseck, and Argat, and maybe Krag; the rest are not worth paying attention to. Regarding dampening, this issue still causes a lot of controversy. Some say that they are completely ineffective, while others consider them useful skills. Everyone decides for themselves; personally, I never upgrade them, firstly, because they take up valuable space, and secondly, they can be partially compensated for by skillfully upgrading the main skills and using artifacts.
I didn't answer anyone's question, but I think that those who decide to master the Orcs will find something useful in my monologue.
P.S. I highly recommend that everyone download the fan guide http://heroes.ag.ru/heroes5/files/. You can find many answers to questions and just useful information in it.