Undead isn't a Unit-Type, it's a Classification in this context. A Unit-Type is what you see under the "Unit" tab in the Object Editor, it's the blueprints for a Unit (ie: Footman, Paladin, Farm, etc). Anyway, you cannot create your own Classifications but you can recreate the concept of a Classification, which is simply marking the Unit in some way so that your triggers can detect it:
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Conditions
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((Triggering unit) has something unique about it) Equal to True
There's a million ways of doing this, but I personally like to rely on hidden passive Abilities. I use Storm Hammers as the base ability since it has no effects that could interfere. Combine that with the "Takes damage" Event and you can easily increase damage against dragons. Here's a working solution:
Step 1:
In the Object Editor, copy and paste the
Storm Hammers ability, set the Art - Button positions to X: 0,
Y: -11, and rename it to "Draconic" with the suffix "(Classification)", that way we can easily understand that this is a special ability reserved for classifying our Units beyond the normal means. Hold Shift while opening a field to allow negative values, like when setting the negative
Y value.
Step 2:
Copy and paste the new Storm Hammers ability from Step 1 and rename it to "Dragon Sword" with the suffix "(Item)". We're going to give this ability 7 Levels instead of 1. This is because the triggers below will use the Level to represent the number of Dragon Swords a unit has equipped.
The math will be (Ability Level - 1) = Number of swords.
Step 3:
In the Object Editor, create the actual Dragon Sword item. It doesn't need any Abilities, the bonus damage will come from our triggers down below. You can still add extra Abilities to it if you'd like.
Step 4:
In the Object Editor, Add the "Draconic" ability to each of your Dragons that you wish to take bonus damage from this Sword. You can hold Shift to bypass the Ability limit if need be. A unit can have an
infinite number of abilities even if the editor seems to say otherwise (the exception being Hero abilities in the Hero Skill Menu).
Step 5:
In the Trigger Editor, create triggers for acquiring and losing the Dragon Sword item:
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Dragon Sword Acquire
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Events
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Unit - A unit Acquires an item
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Conditions
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(Item-type of (Item being manipulated)) Equal to Dragon Sword
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Actions
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Set VariableSet Dragon_Sword_Item_Ability = Dragon Sword (Item)
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-------- --------
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-------- If the unit doesn't have the ability yet, Add it and make it permanent (so it's not lost upon death): --------
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If (All Conditions are True) then do (Then Actions) else do (Else Actions)
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If - Conditions
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(Level of Dragon_Sword_Item_Ability for (Triggering unit)) Equal to 0
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Then - Actions
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Unit - Add Dragon_Sword_Item_Ability to (Triggering unit)
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Custom script: call UnitMakeAbilityPermanent(GetTriggerUnit(), true, udg_Dragon_Sword_Item_Ability)
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Else - Actions
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-------- --------
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Unit - Increase level of Dragon_Sword_Item_Ability for (Triggering unit)
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Dragon Sword Lose
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Events
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Unit - A unit Loses an item
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Conditions
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(Item-type of (Item being manipulated)) Equal to Dragon Sword
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Actions
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Unit - Decrease level of Dragon_Sword_Item_Ability for (Triggering unit)
Step 6:
In the Trigger Editor, create a trigger that detects whenever a unit takes damage. This can only be done in version 1.31+, otherwise, you'll need to rely on something like Bribe's Damage Engine. Technically you could use Damage Engine in later versions since it provides many useful features, it's just a big import and I wanted to keep things as simple as possible for you:
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Dragon Bonus Damage
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Events
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Unit - A unit Takes damage
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Conditions
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(Damage From Normal Attack) Equal to True
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(Level of Dragon_Sword_Item_Ability for (Damage source)) Greater than 1
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(Level of Draconic (Classification) for (Damage Target)) Greater than 0
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Actions
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-------- Note: This Event happens BEFORE damage is actually taken! --------
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-------- --------
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-------- Define how much bonus damage you want the swords to add: --------
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Set VariableSet Dragon_Sword_Bonus_Damage = 15.00
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-------- --------
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-------- Calculate how many swords the unit has: --------
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Set VariableSet Dragon_Sword_Item_Count = ((Level of Dragon_Sword_Item_Ability for (Damage source)) - 1)
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-------- --------
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-------- Calculate the damage based on the number of swords: --------
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Set VariableSet Dragon_Sword_Bonus_Damage = (Dragon_Sword_Bonus_Damage x (Real(Dragon_Sword_Item_Count)))
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-------- --------
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-------- Finally, add this bonus damage to the total damage that the unit is about to take: --------
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Event Response - Set Damage of Unit Damaged Event to ((Damage taken) + Dragon_Sword_Bonus_Damage)
^ Note: You may want to change the Event to this earlier damage step, I forget how the calculations work:
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Unit - A unit About to take damage
That's it, you now have an Item that deals (15 x Sword Count) bonus attack damage to any Unit with the Draconic ability. So you just need to Add "Draconic" to your Dragons for it to work. In my example map I added it to the Peasants since it was easier to test on them. (I was in the middle of making this when Axolotol posted, sorry for hijacking the thread)