Play against Necropolis.

The conclusion is: he has no chance, because he won't be able to rush you. The game will definitely reach at least the mid-game, and most likely the late-game... well, you know what Orcs are capable of in the late-game ;)
Against him, I think you should focus on:
1 - Attack (tactics - battle frenzy - stunning strike)
2 - Suppress Spells
3 - Leadership (muster troops - aura of swiftness - war cry)
4 - Luck
5 - Battle Shout
6 - At your discretion
Machines are not needed. You can take Suppress Darkness if you are sure you won't miss. Attack and Leadership are a must!!! And definitely as written, so that due to tactics and the aura of swiftness, you can deal one hit at a time and reach the liches, who will deal less damage up close.
There are no restrictions on the army, just level up...
Best heroes:
1 - Krag (already has attack with battle frenzy)
2 - Goshak (due to mega evil killers and reinforcements)
3 - Shaq'Karagut (for the late-game with wyverns and defense)
Just level up thoughtfully, and the Necromancer won't have a chance ;) That's the whole trick...

Good luck in battle. Scatter him across the graveyards :smile19: