How to defeat Deleb on "Old Friends"?

In my opinion, only other machinists like Hafiz and Kaspar can stand against Daleb.

How to play as Kaspar: we get Chaos, Deadly Cold, and look for an ice spell + we definitely take the Necromancer's Sign (even if the demons eat everything, we can still cast the spell later). First, we destroy the Ash Pylon Ballista (if it's a ring, the tent will also be destroyed). Your army should have an advantage, so you'll hold out (skeletons are already good against the ballista, and zombies are quite durable). Also, take the Plague Tent, it will help in destroying the enemy army.

For Hafiz: Cold is not necessary here, any spell is enough (for example, Fireball, learned from mages or passed on from a Nazir). We take the second-level Grem, divide them in half, use one group to disable the ballista, and the other to destroy the opponent's army. Education is essential here + if you manage to get Logistics, take Keen Mind (with it, the hero can go before the demons, and they will take less mana. This applies to all Chaos heroes, by the way). There is a second option: Light Magic + Evasion. Evasion severely reduces the ballista's damage + the rest of the buffs follow. The demons will be in a very bad situation.

Vittorio: if he levels up, in my opinion, he becomes the strongest machinist (well, maybe after Kaspar):D. At high levels, his ballista is the strongest, and his army is powerful. We take Light + Evasion - and it becomes very tough (the main thing is to have enough mana). I've tested it myself.

Orcs: Tilsek or Haggesh, but I prefer Haggesh. We level up machines, Logistics, attack with Flaming Arrows and Battle Fury, and definitely Defense with Resistance + we take rings with +2 HP for units. The peculiarity of their racial ability is that increasing the health of units VERY SIGNIFICANTLY reduces the incoming damage. We also level up Last Stand, use Goblin Tricksters in pairs, and kill all the demons (by the way, this is also an option for Vittorio). Then we attack with the main army, cast War Cry on the Centaurs, and basically the game is won (the Centaur ballista won't penetrate). If it's Tilsek, you can strengthen the Goblins or Orcs if there are not enough Centaurs.

Dark Elves: we accumulate a lot of mana and use Tricksters on the demons. If there isn't enough mana, *oops. There is a second option for Tricksters, but it's difficult to do with one computer. We level up Leadership with Speed Aura and attack with Tactics, take Beasts and try to hit the demons with them. Then we buy out what's left, attack with the whole army, and hit with Chaos.

Dwarves: Ingvar can be very good, but you need to play carefully. We level up all defenses (Resistance + Last Stand), Chaos up to Deadly Cold, attack with Battle Fury, definitely Education and Rune Mastery, and if we're lucky, Logistics with Surprise Attack. We accumulate resources (depending on what runes we get). We use Rune Warriors or Shieldbearers in pairs, destroy the demons with magic (we constantly use runes to restore mana), buy them out, and attack with the whole army. Cold on the ballista, then either continue with magic on the army, or teleport to the Shieldbearers, and they will quickly deal with everyone. Something like that.