Well, to put it short, it feels as if the computer player is using some sort of cheats :P buying units at way cheaper prices or whatever (or possibly just abusing the portal between Inferno cities) and no matter what I do, it brings the unbeatably huge army to the field and wrecks me. The few walkthroughs on the 'net pretty much just say "Go there and beat the computer" - if it was that easy, I wouldn't be looking for one. :P

Help?

I found Armageddon Blade levels much easier by having all my heroes that carry over use up all the permanent bonuses on the earlier levels. i.e. before finishing the level make sure that every hero that carries over is at maximum XP and has visited all the permanent +1 or +2 Attack, Defense, Power, Knowledge dwellings, learned all the spells and obtained all the useful secondary skills from Witch huts.

Did you do that?

Sometimes it might also help to restart the level by loading the last save from the previous one so you get a better random seed.

Other than this generic advice I can't offer you much since I played those really long time ago. Hopefully someone else will give you better help.

Well, I now managed to (somehow, don't quite know how, myself) hold my own defensively (mostly), but the computer rebuilds its armies and attacks too often to go on the offensive myself.

(and does that from two directions, either the road in the north, or by boat by the south Conflux city, so I can't just beat it and move on - I just tried to send my biggest army to cut off its sea route, and it chose just that moment to attack by land, good that I saved the game before the attempt)

If I remember right, in that scenario there is no carry over heroes, but two of yours start at level 12 and will get quite a lot of random stats on them at the start. It is cheaty but very tempting to take few tries to get better skills, you can land even with logistics on both your knights, and it wouldn't be for me too shameful to look who's in the tavern too.

The enemy have 5 cities owned at the start, all equipped by portals, and a heroine who has town portal spell on her. AI has no shame to use that to the best effect, so it is rather brutal start.

From what I remember, I went all out ASAP, with maximum efficiency and no wasted moves, and took the inferno town behind the gates before first week end, then miraculously survived her counterattack, killing her in the process. Then I went after the town on the island next to your conflux port.

As soon you have two inferno towns, use those portals for your own benefit.

Without their superheroine on the table, it was way too easy from that point on. But, it wasn't on the first try, she won't attack if you will look too threatening, and their army will grow much faster than yours in the first month or so.

I think they only ever visit that island town by portal, so you can catch that place under defended, and it may even be a good first pick on a slow burn, then followed by the gate town where your two armies merge. Not sure can that plan be pulled in the first week, probably not.

Alernatively, if you're able to sit that first month out doing more damage than receive, you eventually should be able to go on offensive. That's probably how the scenario was intended.

There is a third vector, a set of two way monoliths linking the south and north sides of the map via an island with black market. Eventually, enemy heroes will use that route to, if you allow that, but it also allows you to get in their back for a bit of diversionary hits if not anything more.