Necropolis vs. Stronghold

:) I thought the question would be completely the opposite... Unbearable Galtran and so on...
Your main mistake, it seems, is that you don't know how to play Necropolis. Why? The main strength of Necropolis is skeletons. And your 1000+ should already be on week 3-4, at the very least... That is, the main advice is to learn how to use skeletons!!! Use them to take difficult objects (like Utopias), use them to increase your attack/defense, and use them to take Serpent Nests and Griffin Conservatories (free Wyverns and Angels in your army never hurt anyone! ;)

So - fight all neutrals, immediately build a Necromancy amplifier, develop 2-3 Necromancers in parallel, fight in different directions to gather as many skeletons as possible. Develop the Necromancy skill as quickly as possible to the expert level, and look for artifacts to enhance Necromancy. Skeletons, skeletons, free skeletons - that's the key to success for Necromancers!;) And use self-healing vampires correctly (that's a powerful ability!).