Thank you!

One more question. How do these "attacks of opportunity work". A unit moves next to a hostile one and gets attacked...?

If a unit moves away from an adjacent hostile unit, and the hostile unit has a melee attack, then the hostile unit gets 1 free attack for that move.

-Any unit can move around Archers (no melee attack) without any fear of reprisals.

-If a cavalry moves past a hostile swordsman, where at least one hex of the cav's move is adjacent to the swordsman, then the sword gets 1 free attack at the point where the cav first tries to leave a hex next to the sword. It doesn't matter whether the cav only goes through one hex adjacent to the sword or all the way around, the sword only gets one free attack.

-If the cav moves one hex while adjacent to the sword and then stops, then the sword gets a free swing. If the cav then moves a second time while adjacent, the sword gets another free swing. Don't try to manually walk your unit adjacent to an enemy melee unit one hex at a time unless you absolutely have to.

Edit to add:
-There are abilities that can force a unit to move, like Fear or Turn Undead. You can use these special abilities to get free attacks of opportunity by mostly surrounding the victim with melee units and waiting. For example, if you manage to inflict Turn Undead (does damage and makes an undead unit flee for a few rounds) on a Bone Horror, you could pack 5 swordsmen around the horror and let them sit without attacking. Normally a Horror will chew up swordsmen, but since they didn't attack the Horror doesn't retaliate. The Horror will be compelled to move, so each of the 5 swords will get one free swing at it as it runs. Don't surround it with 6 swords, because then it has no way to move.

-As far as retaliation goes, walkers, swimmers, and floaters are all on the same elevation. Flyers are on a separate elevation. Swords and eagles can walk circles around each other without either incurring any attacks of opportunity, but swords can't walk around swords and eagles can't fly around eagles without incurring free attacks.

-If a melee unit is unable to attack, like if it has been Entangled, then it can't make attacks of opportunity; an entangled unit can be moved past with impunity.

What about number of attacks? How is that determined?

Incidentally, where are you getting all this info from? Is there a website with resources that includes game mechanics?

What's the best strategy regarding transfer? I'm taking items since they feel more "permanent", then if anything left a unit or two, and the remaining in gold.
On ending level one had a helm +1DEF and a choice of a weapon +1ATT or +1DAM. Choose attack, since I figure changing increasing damage gives an avg of 0.5 damage only so the +1ATT with its 10% to hit increase is better.

Base for melee is two attacks. The "Extra Strike" ability gives the unit a third which is NOT retaliated against. Extra Strike does not give the unit any extra retaliations.

Archery gives 2 arrows of 4 att and 2 damage base.
Poison Darts gives 3 darts of physical + poison damage, 3 att, 1 dam.
Sling Stone gives 4 shots, 3 att, 1 dam.

Most magical and elemental attacks give one shot.

Manual, knowledge from others, and hard won experience over many games and turns. I've already linked you to the AoW Heaven site, which has some information.

I've also made a custom map for testing things. I know Southern also has one, and I'm sure a few other people around here have one of their own.

I prioritize a good hero foremost, maybe a second hero if they serve some purpose (like a low level, high Spellcasting hero to use as a mana battery). One or more items, with priority going to good abilities (first strike for my leader), then good value (either cheapies like a 40 point Helmet, or something that balances bonuses and cost). Early in the campaign I might take a good unit (ex. the goblin beetle followed me for a few missions until hero + item costs prevented me from keeping it), with preference for scouting (good move, flying, good vision, etc) or some useful ability (like healing). The last dregs go to mana for easier spell casting, but gold to offset initial costs in a map would also serve you well while you are learning the ropes.

If I have a choice between +1 attack or +1 damage for the same point cost, I'll take the damage. Damage costs 10 level points to increase while Attack only takes five. I'll balance point costs versus stats, trying to achieve good long term value from items since items you possess at the end of a mission can be chosen for the next. Consider what your spells, both now and in the future, can do for you when choosing what things to keep for long term and what to spend points on when leveling. No need to buy Forestry if you can cast the Earth spell Free Movement, for example.

Fantastic thread!

How does this mana battery thing work, does the hero work like a node if they have spellcasting?

How much improvement to road movement does enchant roads give?

Does your main hero risk domination/charm/seduction?

ZFR, we have a newbie (Arnuz) in an active Shadow Magic MP game right now, so SM questions are getting answered. You might want to monitor that thread for when you move to SM.
https://www.gog.com/forum/age_of_wonders_series/aowsm_pbem_sign_up_and_turn_log_map_tbd

Yes, every hero with the Spellcasting ability generates mana each turn, similar to a node. They generate 5 mana per level of spell casting, so a hero with Spell Casting 1 generates 5 mana each turn while a hero with Spell Casting 5 generates 25 mana each turn. Your leader generates an additional 5 mana each turn on top of that.

In the campaign, you can spend points to carry heroes, items, and some units from map to map with you. Higher level heroes cost more points which prevents you from swamping each map with a horde of max level heroes and rendering the campaign difficulty a complete joke.

The mana battery hero is one that maximizes their spell casting ability while minimizing their level so they can generate as much mana as possible while requiring as few carry over points as possible. His whole purpose is to maybe cast buff spells on your leader and primary hero at the start of each map, then sit behind the lines and not gain experience for killing things while generating mana to enable spell casting and spell maintenance for your leader and primary hero.

Enchanted Roads allows your units that move on roads to use one less move per hex. Base cost is 4, roads reduce that by 1 (down to 3), and Enchanted Roads reduces it by 1 again (down to 2). 2 move per hex is a hard coded minimum cost; I don't think there is any way to get it down to 1 move per hex.

The move reduction may sound small, but it works out to be much better than you'd think. Take a standard human infantry with 26 move. Each turn, they can cross 6 hexes of grassland, 8 hexes of road, or 13 hexes of enchanted road.

Of course, this spell requires that you actually have roads to use. If there aren't any roads, then you'll need to construct your own if you want to get any use out of the spell.

Your leader is completely immune to any effects that would cause him to change sides. I believe he can suffer from combat effects like Fear, but he can't be converted to some other player's side.

Any non-leader heroes you have ARE at risk from any abilities that can target them.

Thanks!

How does this combine with freedom of movement? I'm guessing that free movement makes units go as quick as on a road, does a free movement unit still use roads and become faster if they're enchanted?
Do flyers use roads?

Normally forests cost 6 move per hex, hills cost 6 move per hex, and mountains are impassable. Cave crawling reduces the move cost when underground from 4 move per hex to 3 move per hex.

Forestry lets a unit move through forests at the base 4 move per hex.

Mountaineering lets a unit move through hills at the base 4 move per hex, and it lets the unit walk through mountains at 8 move per hex.

Side note: Ending a turn on a mountain hex can be a great defensive strategy as long as you pay careful attention and make sure you have enough movement to reach one; If you are on a mountain hex, most units can't attack you. Be advised that if a unit with Free Movement is on a mountain, has free movement dispelled, and doesn't have Mountaineering/Flying/Floating from some other source, then the unit dies immediately. There is a similar issue with having Water Walking dispelled while on a water hex; make sure you don't lose an important unit (like your leader) to this kind of shenanigan.

Free Movement gives a unit the Forestry, Mountaineering, and Cave Crawling abilities.

A forest can't be in a hex with a road; you can clear forests from around a town by building roads, which will also allow farms to be in the cleared hexes. This is more of a neat thing to know than a usable trick. Considering the cost of building a constructor, paying maintenance on that constructor, and the cost of laying down roads, it generally isn't cost efficient to try and road your towns to clear forests for extra gold. While I'm on the topic: forests can expand to neighboring open hexes; the chance is very low but I've seen it happen. A forest will NOT expand onto a hex with a road.

Similarly, a mountain hex can't have a road in it, and you can't build roads underground (I'm not sure if it is possible to place roads underground manually while creating a map).

Take all that together, and the answer to your question is that Free Move units move on roads at the same pace as any other walking unit: 3 move per road hex as default, 2 move/hex with Enchanted Roads.

Flying units do not make use of roads. They travel through mountain hexes at 8 move per hex and any other hex at 4 move per hex. I'm pretty sure Floating units use the same overland movement rules as Flying units, though floaters can't fly over walls.

I just checked. Roads can be placed on surface terrain, and cannot be placed on dirt (underground) terrain.
But if you edit the game's files, you can place surface terrain on the cave levels, and thereby put roads in the caves when making a map. I don't know if you can build cave roads with a rebuilder during a game, though.

You can place roads in the editor on ordinary surface terrain like grass etc, even if it's placed in the caves. Don't think mountains are possible, and I don't know how that could be hacked in, and then it might not grant mobility anyway to non-mountaineers, though it would probably allow dwarves to go through mountains faster.
As for building roads in caves - I'm not sure, it might be possible to build roads on grassland etc placed in a cave level.

My Enchanted mace has an option of selecting magic attack and attack when I view it. What's the difference?

Doesn't it just mean that magic damage gets added to each attack made by the hero using that mace?

The "attack" is basically "strike", and is redundant.

"Magic Attack" means the mace gives your melee attack the magic damage property while the mace is equipped. It gives the hero's attack an additional vector for applying damage (magic, in this case). There are four states of damage immunity: weakness (extra, either +50% damage or double damage, I don't recall which), normal (no effect), protection (half damage), and immune (no damage). Defenses have to cover ALL incoming damage vectors in order to reduce damage. A unit that is attacking with Physical and Magic damage can hit a unit that is only Physical Immune.
Southern, is it possible to remove "Strike" from a hero? Maybe they only have a ranged attack, unless you equip them with an item that provides Strike?

Yes, but it will crash the game if you accidentally use round attack without strike.