I've played a ton of Oblivion. Once you really understand the mechanics of a game, it starts to be fun to put the game on the highest difficulty and try to get through it. The best strategy I have found that I don't consider to be borderline exploiting the game involves ridiculously powerful poisons.

First off, here's what you want to have for this to work:

1. Invisibility spell (you don't actually NEED this, but it allows you to take zero damage instead of a little damage).
2. 100 alchemy and master level equipment (these things can be lower, but obviously it's ideal to max out your alchemy potential when poisoning).
3. A dagger enchanted with 100% weakness to magic. This can be for a very short duration.
4. A spell on touch with 100% weakness to poison, 100% weakness to magic, 100% weakness to shock, and 100% weakness to fire OR frost. Again, this spell can have a really short duration (which makes it very affordable).

What you are going to do, then, is create the most powerful damage potions in the game. These come in two possible varieties, both of which require Shivering Isles.
1. Damage Health + Shock Damage + Fire Damage
OR
2. Damage Health + Shock Damage + Frost Damage

- The first one is easiest to create with the following ingredients: Black Tar, Steel-Blue Entoloma Cap, Cairn Bolete Cap, and Spiddal Stick.
- The second one is easiest to create with the following ingredients: Milk Thistle Seeds, Black Tar, Ectoplasm, and Frost Salts

All these ingredients can be mass produced using the except Black Tar. However, you can harvest a massive amount of Black Tar in the southern part of the Shivering Isles, and there are also a lot of samples to be found in some people's houses. Furthermore, both of these potions will have a weight of 0.1 which is nice.

Anyways, let's take the first poison as our example. With 100 in alchemy and master level equipment, the poison will have a base damage of:
- 9 Shock Damage a second for 37 seconds
- 9 Fire Damage a second for 37 seconds
- 8 Damage Health a second for 30 seconds

Here's the strategy to increase this damage, step-by-step:

1. Cast invisibility on yourself
2. Walk up behind the enemy with your Weakness to Magic dagger, and hit the enemy
3. Quickly cast your multiple weakness spell on him/her
4. Coat your dagger in the poison and hit the enemy again
5. Cast invisibility once more and watch the enemy die.

The amount of damage this does is staggering. Let me compute it.

You first hit the enemy with 100% weakness to magic. This multiplies the effect of your subsequent spell by 2. Thus, in this case, you end up with the spell creating 200% weakness to poison, shock, fire, and magic. Now let's compute the damage for each part of the poison after all of this.

The shock damage is normally 9 a second. However, with 200% weakness to shock, that damage becomes 27. With 200% poison weakness added onto that, the damage becomes 81 a second. The same happens with the fire damage (it becomes 81 a second). The damage health effect is a bit different. It is considered an offensive magic effect that resist magic works on. Thus, I believe that weakness to magic affects it as well, whereas, it doesn't affect the other two effects. You initially created a 100% weakness to magic with the dagger. You then cast a spell that created another 200% weakness to magic. I believe these stack, meaning the original 8 damage a second becomes 32. Add on the 200% weakness to poison, and the damage per second becomes 96 per second.

As a result, this poison is doing 258 damage a second!!!

Now let's think about how much damage this poison will do over the course of its effect. The Shock damage will do 81 damage a second for 37 seconds. That is 2997 shock damage. You will also do 2997 total fire damage. The damage health effect does 96 damage a second for 30 seconds. That is 2880 damage.

Added together that is 8874 total damage!!!


This will kill anything incredibly quickly, even on the highest difficulty. It's worth it to note that this even works on stuff with 100% resistance to poison, as the spell you use will simply make them 100% weak to poison instead of 200%. This will make you do like 6000 total damage instead of 8874, but that will still kill anything anyways.

Since you use invisibility to get close and use invisibility at the end, it unlikely an enemy will get more than one hit on you. Most of the time, they won't get any in if you sneak up behind them (so they have to turn around) and do it quickly.


EDIT: I want to point out the following. The enemy with the best resistances to this that I can find are Liches who have 25% magic resist (which limits the effectiveness of the original weakness to magic dagger hit a lot) AND 100% weakness to poison (along with 25% weakness to fire). However, I have calculated that you will STILL do 107 damage a second to them and 3702 damage total. If you are level 50, a Nether Lich will have 645 health. Since poison damage is not affected by difficulty, this means that the Nether Lich will only live 6 seconds with this poison.

Alchemy and poisons rock in Oblivion.