Oblivion:Destruction

Destruction magic provides many means of inflicting damage on enemies.  Destruction spells use elements (fire, frost, or shock) and pure magic to damage health; an enemy's fatigue, magicka, skills, attributes, weapons, and armor can also be reduced either permanently or temporarily.  Weaknesses can even be inflicted on enemies, amplifying the effects of subsequent spells.

In-game Description: Cast spells to inflict magical fire, frost, and shock damage, or reduces resistances to magic attacks.

Mastery
Mastery Perks
A Novice (destruction <25) can only cast Novice level Destruction spells.
An Apprentice (destruction 25-49) can cast Apprentice and Novice level Destruction spells.
A Journeyman (destruction 50-74) can cast Journeyman, Apprentice and Novice level Destruction spells.
An Expert (destruction 75-99) can cast Expert, Journeyman, Apprentice, and Novice level Destruction spells.
A Master (destruction 100) can cast all Destruction spells.

Skill Benefits
As your destruction skill increases, the Magicka cost to cast destruction spells decreases, according to the following equation:
 Cost = BaseCost * (1.4 - 0.012 * Min(Skill, 100))
The maximum value for Skill in this equation is 100; increases past 100 will not continue to decrease spell-casting cost.

Skill Increases
You gain 1.2 experience points every time a destruction spell is cast upon an appropriate target, regardless of the magicka cost or damage inflicted. The target must be living; this includes yourself. 

General tips for increasing spell-casting skills are provided at General Magic Strategies. One drawback of all standard destruction spells for practice is that they require a target; General Combat Strategies provides useful tips for finding enemies to practice upon.

Creating a custom practice spell for destruction is the best way to train this skill. The weakness effects are all very cheap (Fire, Frost, Shock, and Poison are all the same cost), and have the advantage that when cast upon yourself do not cause any permanent damage.

Another option is to create a custom Disintegrate Armor or Disintegrate Weapon on self spell, if you wish to simultaneously train destruction and Armorer skills.

See also:
Increasing Skills: General tips on how to improve your skills semi-naturally.
Trainers: Pay for destruction lessons.
 
Skill Books: Books that provide lessons in destruction.
Increasing Attributes: Tips on training skills to improve the Willpower attribute.
Free Skill Boosts: There are a couple of free destruction skill boosts available.
Magic Items: There are multiple generic items with the fortify destruction enchantment.
There are no Unique Items that fortify the destruction skill. These do not include Leveled Items such as those received from quests, or Artifacts.

Dialogue
When your skill reaches 70 or higher, NPCs will start saying: "There's a charge in the air.  Been casting some destruction spells?"

Character Creation
The following races provide initial skill bonuses in destruction:
+10 bonus: Altmer, Dunmer

The following standard classes include destruction as a major skill:
Battlemage, Crusader, Healer, Mage, Nightblade, Sorcerer, Spellsword, Witchhunter

All characters start with one Destruction spell: Flare.  If you choose Destruction as one of your major skills, you will start with two extra Destruction spells: Cold Touch and Shocking Touch.

Magical Effects
A list of all standard destruction spells can be found on the Spells page.  The following individual effects are all considered to be part of the school of Destruction (see the individual effect pages for full details on availability; the Magical Effects article also provides a summary):



Messages
The following table provides the messages that are displayed when your Destruction skill levels up.



Notes
Picking a race and/or birthsign  that boosts Magicka can help in being able to cast more spells in rapid succession or more powerful spells as a master of destruction. 
Destruction magic is arguably one of the more demanding schools of magic, requiring constant use of (expensive) spells to deal sufficient damage to kill your enemies. As such, it can prove difficult to find the time and magicka to use other spell schools in combat. If you desire to use a larger variety of spells, then you will likely find it necessary to deal damage with some sort of weapon or fall back on a summoned creature.
For characters who can both fight and cast, one possible approach to Destruction is to use an elemental damage-enchanted weapon and the appropriate Weakness to Element spell.  A decent (and fast) elemental weapon combined with a Weakness spell can deal more damage than elemental damage spells for far less magicka.  At apprentice-level Destruction, you can cast an on-touch 100% Weakness to the element of your choice for 17 seconds.  At journeyman level, you can also cast on-touch 100% Weakness to Magic for 16 seconds, and they will both amplify the elemental damage.
The Skingrad Mages Guild specializes in destruction; Druja, Adrienne Berene, and Vigge the Cautious sell the most destruction spells.
Once your combined Fame and Infamy reaches 50, you can visit the Magnus heaven doomstone to receive the greater power Skein of Magnus.  One of several benefits of this power is that it fortifies your destruction skill 15 points once a day for 120 seconds.