Iron Maiden Guide
Note that the difference between Amplify Damage and
Iron Maiden is that when you hit a monster under Amplify Damage status,
the monster will undergo FHR animation (Damage > 1/8 HP).
If the monster or player is under Iron Maiden, the attacker will likely
become stunned immediately after they swing.
The difference is basically the timing the FHR animation occurs. If the
player and its army attacks quickly and a decent amount of damage,
Amplify Damage is preferred, since the opponent will be continuously
stunned. However, when the opponent is under the influence of offensive
auras, such as Fanaticism or Might, then Iron Maiden would be the
preferred spell of choice, since the monster will be stunned when you
are in the greatest position of vulnerability. That gives a window to
either hit them or escape.
This only applies when given that the player has invested a number of
points on IM, or the monster hp / damage ratio will be inadequate to put
the monster in FHR animation.