Mine must be buggy then, because when I mouse over a unit skill, it just pops up a new window with that skill’s name, period 
Anyhoo, crossposting this from another forum, a guide on Heroes/Agents - I did not write it but it’s good stuff and worth knowing. Spoilered for sheer length.
[spoiler]All right, if there is one thing that comes up a lot it’s heroes, so this is me doing a giant hero effortpost on all the heroes in the game and what they do. Yes really.
First off, I’ll cover on-map actions, which is often the most important and most annoying part of using heroes. There are a couple of broad archtypes that nearly all heroes fit into regardless of race, having the exact same set of slightly renamed campaign map abilities. Except Dwarves but I’ll get to that.
The Wizard
Empire Wizards, Chaos Sorcerers, Necromancers, Shamans, all go here. By default Wizards have the ability to reduce construction costs for the province they are in when deployed by about 10%, with an extra 10% for the first point in their bottom skill chain. This is actually fairly useful if more than a bit micro-heavy, it’s an easy way to upgrade your capitol province for cheap if nothing else.
Otherwise Wizard agents can buff their effectiveness at assaulting armies, damaging buildings, and give themselves a small buff to assassinate. Deeper in the chain they can learn an embed army ability to increase magic item droop chance, (Yay?) deploy to reduce winds of magic slightly, or boost the effectiveness of block army.
To sum up they are super annoying in the hands of the AI because they can do all the poo poo that will drive you crazy but because they aren’t especially good at any one thing are rarely worth skilling up as agents for the player. (Plus, you know, giving up actual magic on the magic guy to be a mediocre agent.) gently caress Wizards!
The mini-me Lord
Thanes, Exalted Heroes, Captains, Wight Kings, all go here. Orcs are the only race who doesn’t get one, but no big loss…
The default ability for all these basic fighter dudes is to increase public order when deployed. It’s not great. They’re further hampered by the first half of their skill chain basically being straight garbage. + assault, + 3 turns siege holdout time, - 3 enemy public order (when deployed) and -15% recruitment costs are you loving kidding me?
Bleh. After you’ve straight wasted 5 skill points they become almost sorta decent, getting a small buff to assassinate chance, the ability to boost recruitment XP when deployed, and most importantly the ability to train up armies when embedded.
These guys pretty much suck as agents, you can get some use out of them after level 8 or so but getting to that point is a drag and even then I consider them pretty meh overall. Training is good but for what it takes to get there bleh. For me they are forever quest fodder. I would say the one good thing about leveling them is that they’re all so tanky by default that ignoring combat skills to go straight to training is no real loss.
The Assassin
Witch Hunters, Goblin Big Boss, Banshee, go here. Dwarves and Chaos get shafted.
Assassins are basically the best agents in the game for a very simple reason. They are by far the strongest agents at pulling off assassinations, and also bodyguard your stacks against enemy agents. The two best skills in one package, leveling these guys up should always be your first priority.
Your default ability is to deploy and reduce the success of enemy agents in that region. It’s less useful than it sounds because they should always be embedded or shanking agents, but that’s fine because this is the only agent type that can start pumping assassinate chance from level 3. They also get the ability to damage walls, block armies, and of course act as embedded bodyguards for your armies to protect against enemy agents.
Literally have all the best agent skills in the game with no downsides and usually have a pretty meh combat tree so you aren’t missing anything. Always go full assassin.
The Priest
Empire Warrior Priests, and oddly, Vampire Heroes go here.
Priests are cool because they heal your dudes, and the two we get are also combat monsters with lots of powerful unique skills, so the only drawback is that distributing skill points can be really hard.
By default Priests can deploy and boost growth in a province. Eh. Luckily by level 3 you can go straight to replenishment for an extra 15% healing in your embedded army, which is actually huge. Once they get over the halfway hump then can learn Heal Troops to double down on replenishment with an extra +10% and also reduce attrition damage by 15%.
This is the rarest agent type, and leveling them up as agents is a bit of a sacrifice but if you have them abuse the hell out of them. My important Empire Armies always get a Warrior Priest and Witch Hunter as soon as I can afford it.
Anyway, Dwarves are special snowflakes, so
Engineers
Level them up for combat, seriously. Engineers have a unique campaign skill tree but it’s not great. They get the Wizard’s reduce construction cost deployment skill, and can eventually buff map movement as an army embed skill. Everything else they have isn’t worth mentioning, even though they get a bit of unique poo poo like +trade goods and - enemy ammo, you’re not going to get much use out of any of it.
Runesmith
Runesmiths are basically a mix between Wizard and Spy. They get the default deploy ability of assassins, (- agent success chance) and can learn the guard army ability later on. Otherwise they’re basically wizards, though with the ability to double down on reducing corruption and enemy winds of magic.
They are actually the best dwarf agents by a mile, but they’re also one of the best combat heroes in the game, so deciding how to skill them up is difficult, to say the least.
Heroes on the Battlefield
More fun then talking about the campaign stuff, if only because it’s a bit more varied. Breaking these down by race.
Dwarf Thane
Oh Thane, why you so bad? Now, by default the Thane is about the tankiest hero in the game, with crazy high armor, LD, HP, and magic resistance, however, unlike similar melee heroes they have no unique combat skills and no mounts, so really it’s just one slow-rear end dwarf model who never dies but doesn’t do anything interesting or improve much with levels. More than anything, they’re just the most boring hero in the game.
Dwarf Engineer
Anyone who has played Dwarves know that Engineers are super great, but seriously, they are. Being Dwarves they get that ridiculous 120 armor despite being a ranged sniper. The Engineer’s combat tree is split about 50/50 between buffing his own ranged damage and buffing allied ranged units/artillery, definitely lean towards buffing allies. Their one active ability is an aoe buff that massively increases firing speed for nearby units, stick your Engineer in the artillery line and keep mashing that button forever.
Runesmith
Runesmiths are all about maxing the combat tree and spamming their three active runes. One of them gives +15 armor in an aoe, and their ultimate rune provides +44% protection from all damage for about 10 seconds. Dwarves are already incredibly tough, but with a Runesmith providing support they can feel literally unbreakable. Neither of these use winds of magic, so the only limitation is cooldown, and you have a skill that reduces cooldown, so…
They also passively increase allied AP damage like a metal wizard, and have a damage rune that drops a short range aoe spell that…does something presumably. The particle effects for it look like poo poo and I can never tell if it’s actually doing damage but it’s free and you might as well drop it on something, I guess.
Goblin Big Boss
The Goblin Big Boss is an interesting Combat hero, and by interesting I mean kind of really bad. This is a melee hero with Wizard level HP. Armor, and LD. They have decent melee stats and the duelist skill but even so being a terribly squishy melee only guy is not a great place to be. They also get a 50% missile block shield like normal goblins.
This guy’s one saving grace in combat is being able to ride a spider for decent mobility, some extra armor and poison attacks. Also they have vanguard deployment, which is neat I guess. You’re not going to be leveling these guys for combat anyway, just don’t be surprised when you do take them into battle and they get splattered.
Orc/Goblin Shaman
Are spellcasters, I’m not going to talk about every school of magic because this is already long enough.
Night Goblins are super weak but keep the general Night Gobbo traits of being sneaky, poisonous and having vanguard deployment. They can also eat shrooms to make their spell cooldowns vanish for 33 seconds or so.
Orc Shamans are a bit buffer than your typical weedy wizard and can ride a boar into battle, giving them actually a quite powerful AP charge attack and increased armor.
Empire Captain
Despite being as vanilla melee hero as they come, has two advantages. Can ride a Pegasus obviously, and also gets the “Hold the Line” active ability normally only available to Empire Lords. It’s an aoe buff unique to Empire that boosts charge defense so fairly useful.
Warrior Priests
Now, the thing with Warrior Priests is that they start with high LD but low armor and melee defense. They loving love to get themselves killed in auto-resolve, which thankfully is made slightly less painful by their healing skills. As level one heroes, they are trash. As high level heroes with their combat tree topped off they are utterly amazing because all of their active skills are insane.
A fully leveled Warrior Priest can massively buff their own attack rating and physical resistance, drop a 22% physical protection buff that works on them and surrounding allies, call down heavy aoe damage in a radius around them, and greatly bolster leadership of nearby units. In between unlocking all their amazing active skills or super good campaign healing, focus on buffing armor, melee defense, and HP, in that order.
Mounts are an interesting question for WP. The barded warhorse is a huge boost to one of their weakest stats, and the increased movement is good for getting where you need them to be, but OTOH 90% of being an effective Warrior Priests is slogging it out on the frontline with other infantry so I’m not sure it’s worth the trade off. Maybe against factions like Vampires with no good anti-large units.
Warrior Priests are kinda weird and hard to level early on because they have the most pronounced power curve of any hero in the game. A high level priest is totally worth it though.
Witch Hunters Like all Assassin type heroes, you’re not going to focus much on boosting their combat skills and that’s fine. With Witch Hunters all you need is Accuse to melt enemy heroes and you are good to go. Accuse has a fairly long cooldown but the damage it does to single models is massive so abuse the hell out of it.
Otherwise the Witch Hunter is a decent shooting hero, faster than the Engineer but shorter ranged and squishier. If you do level up combat focus on buffing his ranged damage and pick up Slippery for the increased mobility. Witch Hunters are good hero/monster snipers but really bad at fighting normal units, even a pack of hounds is troublesome for him to take on solo so keep him safe.
Empire Wizards
Are Wizards. They can pick up Pegasus at high levels which is always useful for a spellcaster.
Necromancer
Well, Wizards are mediocre agents and Necromancers don’t bring any combat spells not available to literally every VC Lord option, so use your freebie Necromancer to reduce construction costs in Sylvania and otherwise get used to sending their useless arses down to the badlands to unlock quest battles. The only thing less useful than a Necromancer Hero is the entirely useless Necromancer Lord. Even their mount option is just an evil horse, because they are the saddest thing.
Wight King
Wight Kings are in a weird place. They are actually stone cold killers on the battlefield with crazy stats, lots of mount options, some unique active buffs, and a 50% missile block shield. OTOH, I’m not sure they’re actually stronger fighters than either type of Vampire and they have the Thane’s campaign skill tree, so fitting them in can be hard.
Probably the one really good use for a Wight King is guarding Kemmler and his noodly little girl arms, so just name your first Wight King Krell and roll with it.
Banshee
Well, they’re an assassin type so obviously battlefield performance is an afterthought. Also they’re ethereal, which is a definite +/- situation. All ethereal units do magic damage, btw, which among other things means they do full damage to other ghost types. They inflict terror and have very high AP damage but actually just have a generic spy-type (Slippery, basically) combat tree with nothing particularly interesting about it, so Ghost Hero pretty much sums up everything they bring to the battlefield.
Vampire
Vampires are regenerating Death Lore wizards with solid melee stats and the Warrior Priest’s campaign chain combined with the Vampire Lord combat chain. The only thing making them not utterly insane is that you can’t skill everything and they only get Hellsteeds instead of Zombie Dragons.
Exalted Hero
Pretty boring (But effective, mind) standard melee hero. The most interesting thing they have going for them is being able to ride a Manticore and having a rare 50% block chance shield.
Chaos Sorcerer
I just want to point out that Sorcerers get 100 armor and decent melee stats because Chaos, on top of having access to some of the strongest magic lores. Only real downside is not getting a flying mount.
And that’s my too long effort post about agents. [/spoiler]
