Walkthroughs for custom maps.

Download link: http://www.maps4heroes.com/heroes3/maps.php?keywords=Scars+of+the+old+wars&type=&size=&difficulty=&sort=3

Genre: RPG.
This map was first created in Polish, and then the author translated it into English.
Plot: Forgotten by deities, you stand alone in battle against other lands. In this extremely difficult task you know that only those who mastered the art of killing are capable of winning.
The map is challenging even for advanced players.
Additional information from the author (Google Translate from a Polish site): Each land has a different starting hero with different skills, as well as a separate story. At the beginning of the game, I recommend that you carefully familiarize yourself with the heroes' skills and the spells they have. The events often hint at the gameplay.
First of all, one should follow the author's advice: first carefully study what each race has at the start to choose who you want to play as. Read below for which options I consider the best. For my part, I will add something the author didn't mention, although it is extremely important: there are very few spells available to learn here, and you will have to fight for the valuable ones.
The map is modern but executed in a "classic" style, without fancy new-age "gimmicks" like heroes specializing in level 6424 skills, bug-using, etc.
Keep in mind that if you rush through the map as quickly as possible, you might miss some of the message texts (the main character's visions), which will deprive you of part of the pleasure: after all, the author put effort into creating the atmosphere and thinking through the history and geography of the world, and some dreams contain valuable hints about what to look for and where.

The map is meticulously drawn and very rich.
An abundance of resources, artifacts, monsters, and visitable objects.
You can choose any race to play except the elementalists (Conflux) and necromancers (they are the main enemies here). Therefore, the map can be played again as another race, and it will feel like a significantly different game due to the need to use the features set by the author.
You have enough time in the initial stage to develop without fearing a clash with the enemy's main forces. If they land on your territory, you can take cover behind border gates, which the enemy cannot enter until they visit a tent of "your" color.
4 "own" cities for each race (one of which contains the Grail) + a number of external dwellings + the ability to assemble the Legion Statue allow one to build an impressive army in just a few months (by the 5th month, I had 400+ hydras!).
Although the map's genre is RPG, there is no linearity or fixed sequence of progression other than the predetermined order of capturing "own" cities: once you enter the world, you can go wherever you want and act as you please.
There are quite a few Seer huts on the map, but all their quests are optional, although some give very valuable rewards.
Dynamic gameplay without any dragged-out stages of progression.
Interesting idea with the border gates. Thanks to it, you will definitely have to explore and visit the dungeon (on some maps it turns out to be optional).
You can choose not to kill the strongest enemy hero, Nameless, if you are afraid or cannot reach him. It is also a plus that he cannot attack you himself.
Many whirlpools and monoliths connecting different places on the map.

A comparison with "The Fall of Atlantis" inevitably comes to mind: starting conditions for all playable sides are very different, and the author's efforts at balancing are visible, but most likely some races are easier to play than others. The picture is completed by the presence of the Grail in the 4th city of each race: remember the special bonuses. At the same time, this explains why you cannot play as Conflux: it wouldn't be so easy to get all the spells here!
As someone already noted in the map discussion, the necromancers (Turquoise), who according to the author's design should eventually start spreading terror among all peoples living on the surface, are actually defeated very easily: you only need to find and visit the blue tent, then go through a monolith and capture Turquoise's only city. After 7 days, the mighty Nameless with his legion of dragons will simply perish, as he has no way to leave his island. To be fair, this is not the author's fault: the reason is likely the well-known "bug-feature" of the game where heroes of some classes sit in cities, do not move and do not attack, regardless of how strong their army is. However, as later turns out, the activity of the necromancers depends on the player's actions: when the player comes to them, they "unfreeze."
Although the dungeon is impressive just by its look, traveling through the system of entrances and exits of the red one-way monolith, which are very numerous, is tedious due to the need to reload saves many times to get to the right place.
An inaccuracy in the placement of some artifacts allows me—after defeating one squad of azure dragons at a two-way monolith in cell 39,61—to visit all its other exits and take the Hell Sword and Helmet of Satanic Fury without a fight (and about 3 more chests, but that's a minor detail).
There are only 2 obelisks on the map standing side by side, and the Grail turned out to be buried in an underground labyrinth; even with the map revealed, it is quite difficult to understand where this place is (though you can peek in the editor).
The guardian before the place where the Grail is buried requires the Wizard's Well, but the message text says "Ring of the Magi".
The gem pond on the swamps in cell 35,63 is located such that it cannot be reached.

Having studied the starting heroes of each of the 7 playable sides, I decided to play as Fortress. The hero here has Earth Magic, Water Magic, Tactics skills, and Resurrection as a specialization. Considering that advanced magic is worth its weight in gold here, this is one of the best options. How right I was became clear later: in 3 cities there are the same level 1 spells, and levels 2 and 3 of the Mages' Guild can only be built in the first city.
I think the second best choice for a traditional playstyle is Castle, as humans have archangels capable of resurrecting. Or, conversely, you can "ignore" magic and bet on brute force—then try playing as Barbarian.
The fact that every new week is an Imp week suggests there is an Inferno with the Fire God somewhere. On one hand, it's nice that there won't be a plague month. On the other—whoever owns that city will accumulate troops especially quickly. Also, imps may appear in places where they will hinder disembarking from boats.
Quite soon I stopped using weak own troops, bringing only level 5-7 creatures (only occasionally taking snakes for speed or "preventive" weakening of enemy stacks).
When I finally captured my last city, the Grail and a fully built level 3 Mages' Guild were there—I didn't have to spend resources building it in the first city, and the spells there (I checked) are the same.
After that, I defeated the minotaurs near the mine and the azure dragons before the green two-way monolith, visited all its exits, and opened a view of their surroundings thanks to the Telescope and Spyglass. I saw the necromancers. But for now, I cannot invade anywhere because border gates of other colors, which I haven't visited yet, stand at all the exits. However, this is good, as enemies cannot burst into my lands through this monolith either. As I mentioned above, I took the Sword and Helmet (they must not fall into enemy hands!). One exception: at the exit in cell 69,8 there is an area not closed by border gates where one can enter without fighting azure dragons. This is an island where seers live, giving valuable rewards.
After defeating the gold dragons, I took the Town Portal scroll they were guarding. And from a seer, I received 100 hydras for destroying the azure dragons.
I visited the mage's hut and saw several places in different parts of the world, including Turquoise's main hero with hundreds of black dragons standing motionless in one spot.
By capturing Archfather's Tower at 3-4-2, I revealed the entire map! I learned few useful new spells, but most importantly: I know where to go for what and whom!
Finally visited the blue tent.
I tried to capture Turquoise's Necropolis and confirmed that it is currently his only one. So, I'll leave him for later: I want to defeat Nameless in a fair fight. And so the enemy doesn't escape, I must either find the Shackles of War or take the Necropolis beforehand.
The behavior of the necromancers turned out to be more amusing than I thought: as soon as I killed the pathetic neutrals on the way and left, Turquoise's heroes immediately rushed into the red monolith.
With many reloads, I managed to exit the red monolith in the north of the dungeon, where I broke the garrison and visited the white tent. All other tents are located there too; you just need to exit in a slightly different place.
Successfully entering the red monolith at the white tent, I came out near the others. Caution: before passing through the white gates, an event will take 500 mana units from you! This is why you must regularly replenish your mana supply (or better yet—double it). And a bit further, an event at the well takes 10,000 gold, and it does so every time you pass. But that's not scary now. I went around all the tents, spent my mana exactly down to 0, and visited the well.
A new hero popped out of the Necropolis; meanwhile, I captured his city and learned more useful spells. I left so the enemy would return to the city, but he turned out to be stupider: instead, he jumped into the red monolith. Most likely (if unlucky), he will perish there, just like the main villain Nameless.
The necromancer was lucky after all: he successfully exited near an unclaimed Necropolis and captured it. So, let him live until I come and destroy him myself. And he began to make up for lost time, jumping through red monoliths, constantly activating veils of darkness and blocking my view of the dungeon in various places.
I defeated the fanatics, took the Holy Sandals they were guarding, and formed the Angel Alliance.
At 4-3-5 Blue was the first to disappear from the map.
At 4-4-2 I destroyed Green.
At 5-1-1 Barbarians disappeared from the map.
At 5-2-3 Red was destroyed.
At 5-3-4 I destroyed Purple.
At 5-4-5 Pink disappeared. Only the last, main enemy remains: Turquoise.
The Wizard's Well required by the guardian before the place where the Grail is buried did not assemble during my playthrough. I found out there is an event that gives the Well, but to reach it, you must give up the Tome of Fire Magic (I had already taken it after defeating 1600 phoenixes). I gave the Tome of Fire and received the Well.
At 6-4-1 I dug up the Grail.
At 6-4-7 I reached Nameless and defeated him. I had wyverns, gorgons, hydras, and azure dragons with me. In the first phase of the battle, he heavily battered my army, but when he sensed things were going south, he began summoning fire elementals and attacking gorgons, while I methodically resurrected the fallen; in the end, the enemy was destroyed without losses, and I received the Tome of Fire and several other artifacts from him.
After that, I tried to find and capture all remaining Necropolises, as well as 2 Strongholds on the surface that I had overlooked.
On the 7th month, 1st week, 6th day I defeated the last necromancer, and I was congratulated on my victory.
Result: 174 days.

If anyone completes the map with other races—let me know. It will be especially interesting to find out who can defeat Nameless, when and how.
After this map, I simply must try to complete another masterpiece by Michael: "Seven Dark Souls". As the author writes, this map is harder, and it's currently only in Polish (but he promised to translate it soon as well).