looking for a fire stick (RF sceptre)

Iron Will doesn't support RF (not dealing any spell damage).
The damage modifier on Doon is global, yes. It's not that crazy, but decent. Obtainable a lot earlier than the Atziri Scepter in new leagues. :)
With very good rare items you might even get enough strength to make it a little better than Doryani's Catalyst, at least for RF where you don't need the 1% elemental leech.

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Lord_of_Error wrote:

With very good rare items you might even get enough strength to make it a little better than Doryani's Catalyst, at least for RF where you don't need the 1% elemental leech.

I would like to contend that statement.

Okay, let's try to factor in the base life you get from doon. It's a max of 35 base life. Let's say a good RF build has 9000 life at max level. Let's say this is achieved with 250% increased life, so all life gains are multiplied by 3.5. So we'll round that up to 123 life gained out of 9000.

So your base DPS gets multiplied by 9123/9000 , a 1.4% "more" multiplier, in essence.

Let's say for the sake of argument that you have a very large amount of % increased damage (fire, burning, etc) sources from not-your-weapon. This assumption benefits you, I assure you (if you don't believe me, start with 0% increases and you will see that doryani's catalyst is just entirely dominant). Let's say it's as high as 250%. You're stacking life way before elemental damage from the tree, at least, so you can get maybe 160% there if you're really reaching for it. Then you get 30% from doryani's invitation, some fire damage from jewelry... and kaom's.

Thus, from here, we can compare the weapons directly.

A perfect Catalyst will provide 110% increased elemental damage. So 360% increased damage with the lower life value. We'll say this lower life value is equal to "1", so the fire damage increase percentage is equal to 4.6 when you multiply.

Now, Doon. This has our special life value of 1.014. We solve for 1.014x = 4.6 and get x ~= 4.53 (it actually should round up to 4.54, but I've been generous in all of these calculations).

Doon gives an intrinsic 10%, which means that we have 260% increased damage so far before the bonus from strength. Now we need 93 additional "increased damage" points to match a perfect catalyst.

That takes 744 strength. That is _not a reasonable target_ for any build. it reminds me of the people also in Gameplay Discussion right now attempting to stack 1500 int or whatever to make that new unique-granted skill not suck.

In short, Catalyst will be better than Doon for RF under any reasonable circumstances. But Doon is still good for its price!

Well, I'd start calculating how much strength on gear is possible for RF characters before factoring in tiny +35 base life:

Chest - Kaom's Heart (0 str)
Shield - Rise of the Phoenix (0 str)
Weapon - Doon Cuebiyari (up to 70 str)
Amulet - rare Amber amulet (up to 112 str / 30 implicit, 50 str + 32 all attr explicit)
Rings - rare (up to 66 str each / 50 str + 16 all attr explicit)
Boots - rare (up to 50 str)
Gloves - rare (up to 50 str)
Helmet - rare (up to 50 str)
Belt - rare Leather Belt because life > strength for damage (up to 50 str)
-----------------------------------------
in total up to 514 strength from gear possible

I haven't played a pure RF character myself so far, however I have a char with RF + Incinerate, from my (reasonable) passive tree I get 350 strength. Combined you could reach more than 800 strength, and at that point Doon gives more damage, independent of other sources for increased damage or the little life boost from its strength mod.

Of course the gear needed is very specific, that's why I said you need "very good rare items". However, I assume stacking strength is not unreasonable for RF chars if you want to get that last bit of base life.

And yea, I'm aware that usually it's a lot easier too just slap on that Doryani's Catalyst.