Ive been studying destruction magic heavily lately, its my best friend in combat. However, i currently read a post that is making me question my understanding of it. This is how a battle tends to go. I have a TON of magika btw so i know its a lot. I cast spells to make up for the lack of other enchantments.
Nighteye (if needed)
Feather (if needed)
Fortify Willpower
Shield
Summon (if deemed necessary.)
Weakness to what ever element i plan i using
Destruction spell of the appropriate element.
I read recently, however, that if i make a spell of relatively low direct damage, but a significant amount of weakness to that direct elemental damage, i will actually do more damage. the reasoning behind it was that the weakness to whatever element im using STACKS???
Example:
Spell: 40 fire damage on target &
100% weakness to fire for 6 seconds on target
1st cast:
100% weakness
2nd cast
200% weakness
3rd cast
400% weakness
4th cast
800% weakness
This is of course assuming that i hit it 4 times within the 6 seconds that the weakness to fire effect will last.
Is this true????
Thanks in advanced!!!
P.S. I play on xbox with all DLC's and no mods.
1. I wouldn't bother with Fortifying Willpower, all it does is increase your regeneration. Unless of course you are suing a mod that makes it more useful. In the vanilla game though it's not particularly useful.
2. Now about your question, it depends on the weakness. Weakness to elemental damage and Weakness to Poison only stack if they come from different spells. Whenever you cast a spell on a target that is still under the influence from a previous cast of the spell, the new cast repalces the old. That probably sounds a bit confusing, so let me give you an example.
Let's say you cast a spell that does 10 fire Damage for 10 seconds on a Bandit. Then after 5 seconds you cast the same spell on the same Bandit. The total damage that the bandit will suffer is 150. When you cast the spell the second time, it first ended the spell that was still on him and then it started again from the beginning.
So you can't cast the same elemental weakness spell over and over to make the weakness more potent. But if you have one spell that causes 100% Weakness to Fire and another spell that cause 100% Weakness to Fire, then if you cast both spells on a target, that target will indeed have 200% Wekaness to Fire.
Weaknes to Magick on the other hand does stack with itself. That's because it makes the target vulnerable to all hostile spells, including Weakness spells. If you have a 100% Weakness to Magick spell (with a sufficently long duration) and you cast it twice on the same target, the target will now have 200% Weakness to Magic. Cast it 3 times and the target has 300% Weakness to Magic. Cast it 7 times and the target has 700% Weakness.
If you have a spell that combines 100% Weakness to Magic and 100% Weakness to Fire (or another element) theWeakness to Fire also gets amplified. So after 3 cast the target has 300% Weakness to Magic and Fire, which in turn means it takes 16x damage from Fire Damage spells ( [1+3] x [1+3] = 4 x 4 = 16 ).
But there is more. If you make two different spells that combine 100% Weakness to Magic and 100% Weakness to Fire it gets even deadlier. If you cast the two spell one after the other, the target will already have 300% Weakness to both Magic and Fire. If you then cast the first spell again the target will have 600% Weakness to Magic and Fire. Then if you cast the second spell a second time the target will have 1100% Weakness to Magic and Fire. At that point any Fire Damage spells you cast will have their damage multiplied by 144. If you cast Flare, the weak little fire spell that everybody starts with, it will do 864 damage. Unless of course the target is a Flame Atronach (or another creature that has 100% Resist Fire) in which case it will take only 792 damage.

The main issue here is the time it takes to layer on all the weaknesses and the fact that if you miss a shot it can screw up your sequence. It's probably best to add 10 Fire Damage to the Weakness spell themselves so you're already doing damage while you're stacking weaknesses. So you'd have two spells that have 100% Weakness to Magic for about 8 seconds, 100% Weakness to Fire for about 8 seconds, and 10 Fire Damage. You'd then tie them to two hotkeys. You'd also probably want to make them area of effect and aim at your target's feet.
When you cast the first spell for the first time you do 10 damage.
When you cast the second spell for the first time you do 30 damage.
When you cast the first spell for the second time you do 160 damage.
When you cast the second spell for the second time you do 490 damage.
If 690 damage wasn't enough to kill your enemy and you cast the first spell for a third time you'll do 1440 damage.
If 2130 damage still wasn't enough to kill your target and you cast the second spell for a third time you'll do 3240 damage. Or you could cast a 100 Fire Damage spell to do 32400 damage. Kind of excessive, but a friend of mine likes to say that if it's worth doing, it's worth overdoing. :chaos:
If you make a touch version of the same spell, it's also advisable to throw in some Absorb Magicka and Absorb Health. They'll only be magnified by the Weakness to Magic, but they'll keep your Magicka and Health up.