Herbie in dev blog wrote:For negative effects, the attacker’s Cunning and Level oppose the target’s Vitality.
You compute two ratios first:
Attacker Cunning / Attacker Level+10
Defender Vitality / Attacker Level+10 (yes, Attacker Level+10 here too)
So, let’s say a Level 5 demon with 20 Cunning is trying to land a negative effect on a Level 3 demon with 10 Vitality. These ratios turn out to be:
20 Cunning / 15 = 1.33
10 Vitality / 15 = 0.67
You take these ratios, and filter them through a chart that looks like this:
Ratio -> %
0 -> 75%
1 -> 100%
2 -> 125%
3 -> 150%
etc.
For 1.33, we get a value of 108%. For 0.67, we get a value of 92%.
Finally, divide the first ratio’s result by the second. In this case, 108% / 92% = 117%. This is the percentage of the tooltip listed chance you have to land the negative effect on your target.
Weakness, Resistance, and Immunity also apply: Weakness and Resistance give large bonuses/penalties to landing associated effects, and of course, Immunity prevents it outright. Heroes also have a large amount of bonus resistance to all negative effects.
I’m trying to get better about explaining this stuff in game… but I’m not sure how I could effectively in a bite-sized fashion. Maybe it doesn’t need to be bite-sized and I should put these explanations in the back of the manual for any interested parties to read?
And this is why I don't think increasing Vitality to counter negative effects is a good idea. If my understanding of the written above is correct, then I am guaranteed to be hit with negative effect if my Vitality is less than or equal to attacker's Cunning. For example, Kasha with its Weigh Sin has Cunning 18 and it means that I am guaranteed to be hit with the ability as long as my Vitality is at or below 18. So my caster with Magic 44 and Vitality 4 will continue to put all points into Magic, 10% increase in damage for every 5 points in Magic is much better than +2 HP for every 5 points in Vitality.