What exactly does Darth Sidious' zeta do for health?

If he has 100% Potency, his health is increased by 100% of his Base Health.

So, say I mod him to have 28,000 health and 100% potency, will he then have 56,000 health?

Nope, base health before mods, that is increased

His Unique only kicks in during battle, so there's a chance that you'd get 56,000 health. (Never tested so someone who bothered to test can chime in)

For other bonus such as 5.88% Health from mods, you must take Base Health (Health before mods and gear from uncompleted gear level)

"Huatimus;c-1380380" wrote:
His Unique only kicks in during battle, so there's a chance that you'd get 56,000 health. (Never tested so someone who bothered to test can chime in)

For other bonus such as 5.88% Health from mods, you must take Base Health (Health before mods and gear from uncompleted gear level)

I haven't tested this particular facet either, but I know with offense on leader bonuses and from offense up, it uses the value after mods as 100% (I have tested that). So my understanding is that all multiplicative effects that happen in battle take the modded value as 100% (crit damage buffs seem to be additive).

What I'm picking up from this is that when I get his zeta I'm going to want to mod him for heavy potency

His zeta isn't that great, I have it and I'm not impressed. The zeta gives you decent potency already so I don't think he needs that much more heavy potency. A potency cross mod sure, but no need to specifically mod for extra beyond that.

What I'm picking up from this is that when I get his zeta I'm going to want to mod him for heavy potency

"Huatimus;c-1380393" wrote:
His zeta isn't that great, I have it and I'm not impressed. The zeta gives you decent potency already so I don't think he needs that much more heavy potency. A potency cross mod sure, but no need to specifically mod for extra beyond that.

I was talking about extra potency so that he has more health

I am more interested in landing those debuffs on the tank due to the increased potency - yes the health will make him last longer, but it seems without the zeta it's hard to get his potency over 24% and then he doesn't land enough DoTs for Zader to feed from.