Talk:Doom Dragon

Battle strategies? For example, did you know that if you only use the 'attack' command along with wish, the doom dragon will not be nearly as ferocious? No summoning, no djinn, no psynergy- it takes a while, but he can be killed with an underleveled party.
 * Really? I'll have to investigate, or someone else should, but if that's true then that's definitely useful to put into the article. Thanks! Erik Jensen (Appreciate me here!) 16:48, 10 June 2007 (UTC)

I'll have to go back 'n play it, but I seem to recall a rather spectacular loss in second stage when he used Djinn Storm followed by Cruel Ruin just before I could get an Iris off... Confirmation on this would be vastly appreciated. AlishaShatogi 17:19, 8 October 2007 (UTC)

Wow, he is not this tough... Why can no one seem to defeat this guy (or dullahan) without summon rushing? Get around to doing some actual leveling with wonder birds, it's not hard... a level 56 team (the level at which every character knows every psynergy) beats this guy easy. 128.120.187.243 23:09, 17 January 2008 (UTC)

Cruel Ruin
Unless I'm mistaken, fire adepts have weaker resistance to Cruel Ruin while earth adepts have stronger resistance to it with wind and water falling in between. No known element fits this though. Tzion 16:41, 4 September 2008 (UTC)


 * That's not true. Garet and Jenna naturally have a lower resistance to earth than to any other elements. I know, this goes against everything we know about "elemental relationships", but it's true (everyone else follows the same pattern). Since everyone is naturally most resistant to their own element, I'd say that Cruel Ruin is a Venus attack. The world&#39;s hungriest paperweight 17:12, 4 September 2008 (UTC)


 * Didn't realize that. Tzion 23:59, 4 September 2008 (UTC)

Damage Multiplier
After reading that Cruel Ruin did additional damage based on your HP, just like a summon, I became interested in knowing the actual damage multiplier used. First, from the information in TFergusson's battle mechanics guide and from my own testing, I derived this formula for damage dealt by a summon-style attack:

$$\mathrm{damage = \left \lfloor \left( \frac{\left \lfloor 256 \left(\frac{dimRatio}{100} \right) \right \rfloor}{256}\right) \left(base + \frac{\left \lfloor 256 \cdot hp \cdot \left(\frac{multiplier}{100}\right)\right \rfloor}{256}\right)\left(1 + \frac{\left \lfloor 256 \cdot \left( \frac{power - resistance}{200} \right)\right \rfloor}{256}\right) \right \rfloor + randDamage}$$


 * damage: final damage
 * $$\lfloor x \rfloor$$ is the greatest integer less than or equal to $$x$$.
 * dimRatio: 100, 70, 40, 30, 20, 10 for summons; the main target will take 100% of the damage, the person next to him will take 70%, etc.
 * base: base damage of the attack. For Cruel Ruin, it's 200.
 * hp: HP of the target
 * multiplier: the damage multiplier of the summon; see the Summons page. For Venus, it's 3; for Eclipse, it's 15; etc. This is what I wanted to find. Note that you can set this to 0 and this formula will work for regular psynergy.
 * power: the user's elemental power in the relevant element. Cruel Ruin is a Venus attack, and Doom Dragon's Venus power is 110.
 * resistance: the target's resistance to the relevant element (Venus in this case).
 * randDamage: a random integer between 0 and 3, inclusive.

For the purposes of solving this equation for "multiplier", I neglected the fact that the game stores only fractions that have integral numerators when the denominator is 256. This was accomplished by using $$\lfloor x \rfloor = x$$, which isn't a terrible assumption given the size of the numbers. I also neglected random damage. This is the result:

$$\mathrm{damage = \left(\frac{dimRatio}{100}\right)\left(base + hp \cdot \left(\frac{multiplier}{100}\right)\right)\left(1 + \left( \frac{power - resistance}{200} \right)\right)}$$

We can rearrange this to get

$$\mathrm{multiplier = \left(\frac{100}{hp}\right)\left[\left(\frac{damage}{\left(\frac{dimRatio}{100}\right)\left(1 + \left( \frac{power - resistance}{200} \right) \right)}\right) - base \right]}$$

I fought Doom Dragon's second form with Felix, Isaac, Jenna, and Mia (in that order). Before every turn, I noted the characters' total HP and Venus resistance. When Doom Dragon used Cruel Ruin, I noted the damage dealt. I did this three times. The results are below.

Trial 1

 * Felix: 645 HP, 139 resistance, 273 damage
 * Isaac: 847 HP, 154 resistance, 420 damage
 * Jenna: 736 HP, 86 resistance, 388 damage
 * Mia: 565 HP, 88 resistance, 189 damage

Trial 2

 * Felix: 766 HP, 149 resistance, 125 damage
 * Isaac: 403 HP, 114 resistance, 142 damage
 * Jenna: 736 HP, 86 resistance, 386 damage
 * Mia: 554 HP, 88 resistance, 468 damage

Trial 3

 * Felix: 874 HP, 154 resistance, 300 damage
 * Isaac: 503 HP, 124 resistance, 373 damage
 * Jenna: 736 HP, 86 resistance, 385 damage
 * Mia: 554 HP, 88 resistance, 186 damage

This data gives us "hp", "resistance", and "damage" in the equation above. "power" is 110 and "base" is 200. Finding "dimRatio" is a matter of knowing the main target of the attack. Even if you don't know, you can just guess; if you get wildly differing values for "multiplier", you'll know that you guessed wrong. Using this trial and error method reveals that the attack was targeted at Isaac, Mia, and Isaac for trials 1, 2, and 3, respectively. We can now simply plug in these values to get the value of the multiplier:

Trial 1

 * Felix: 39.712
 * Isaac: 39.960
 * Jenna: 40.068
 * Mia: 39.943

Trial 2

 * Felix: 41.462
 * Isaac: 40.259
 * Jenna: 39.721
 * Mia: 40.004

Trial 3

 * Felix: 39.983
 * Isaac: 39.975
 * Jenna: 39.548
 * Mia: 39.516

The average is 40.013. All the summon multipliers are integers, so it seems pretty clear that the multiplier for Cruel Ruin is 40 (the same one used for Iris, incidentally). The slight variations from this number in the data above are easily accounted for by the assumptions I made. I've added the damage multiplier for Cruel Ruin to the Doom Dragon page. If anyone wants to do a similar analysis for the other summon-style attacks, feel free. Cheeseoman 18:14, November 27, 2009 (UTC)

I should mention that it's a good idea to calculate the final damage using the first formula above to verify that the multiplier has been calculated correctly. If you use 39 or 41, you'll find that the damage is too low or too high, respectively, in many cases. Thus, the damage multiplier has to be 40 (or something close that accounts for the fraction storage issue). Cheeseoman 19:18, December 3, 2009 (UTC)