Hello,
Since a couple years ago, in the arcade and in missions, monsters and treasure boxes will sometimes drop temporary buffs. There is a defense one, a damage one, and a speed one.
The effect of the speed buff is pretty obvious, and I doubt anyone cares about the exact values.
The damage buff is self explanatory. You get increased damage for a short time. It should be pretty easy to figure out the math behind it since exact damage information is available on every hit. For some reason, the wiki contains close to no information about it.
And the last one, the defense buff, seems extremely obscure to me. What does it do? Defense and resistance are different stats in this game, so I would bet it only affects shields. But what's the exact difference? does it have any impact on status effects, or just pure damage?
The caption "Defense up!" doesn't really help, I can't find any information about it anywhere, not even a wiki page that aknowledges it's existence. Also, I've been playing in french for a long time (please forgive my bad english), and the caption is even weirder. It's "Défendez-vous!", which roughly translates to "Defend yourselves!". It sounds more like a boss is gonna come to attack you instead of you having just obtained a buff, but I guess it's just a terrible translation.
I didn't really care about this information before, since I try to avoid attacks anyway, so the defense buff doesn't affect my playstyle. But I recently noticed that Drakon's second spell (fire barrier or something) also gives the same caption when activated, and the same status effect appears next to your health bar. I'm trying to figure out exactly how it behaves to use my Drakon more efficiently.
Thank you very much
This is a good question. After some Google searching, I have not found a clear answer. So it's hard to find, if it exists at all.
Presumably the defense boost increases your defense (armor damage protection). When an incoming attack hits you, your damage protection gets subtracted from the incoming damage, and whatever is left over is subtracted from your health. So probably the defense boost increases your damage protection and therefore decreases the amount of damage that you take.
Some of your other comments --- about damage vs. status, and shields vs. armor --- don't make sense to me. Why do you think that the boost affects shields? Why are you considering status? If you haven't done so already, consider reading the wiki pages Defense, Damage, Shield, and Shieldbearer's Guide.