Tactics for Necropolis.

In my opinion, when playing as Necropolis, you should accept that you will most likely not have the first turn.
Therefore, you need to be prepared for such "unexpected events." Look for opportunities to engage in melee combat by any means: teleport Skeletons to the enemy, use mass haste (although, in principle, if you have Teleport, you can do without mass haste - there are not many powerful units in Necropolis anyway); dispel spells; use Tactics, etc.

This is understandable. But even if slowed, the dragon will still have a speed of 9, which means it will move faster than almost all enemy ranged units (who among the ranged units moves quickly? Wizards, Snipers, Titans, it seems like that's all), so there will be an opportunity to do something before they shoot you down (teleport/hasten/dispel).
Without dragons, the situation is worse - with a speed of 4, they will all thoroughly damage us from a distance, and only then will they give us a chance to move.