A fast, demoralized griffin/air elemental/ifrit, etc., arrives – heroes die bravely, especially if there aren't enough genies to slow them down and then block all the stacks of flying creatures.

Sometimes, neutrals, especially at higher difficulty levels, attack heroes and ignore everything else until they are defeated. In such situations, neither Nagas, nor Dungeon Guardians, nor Titans will help. Elixirs of Immortality are the only salvation:smile04:

Genies can at least delay them with the Song of Peace, but the rest (except for Vampires and Nightmares) will drag them to the castle to be killed. :) (Of course, I mean the period of the game when the heroes are not yet leveled up and don't have much magic.)