Herald of Plague & deadly Herald???

Do Herald of plague and deadly herald even work together? can someone please explain to me how exactly they interact? it says supported in the game but the herald doesnt do any damage at all sooooooo what does it even do ?

I also want to know. Herald of Plague does not do direct damage, but spreads the most damaging poison on the enemy that died to other nearby enemies. So does that poison get a damage boost from Deadly Herald or not??? No way of seeing in the gem stats

"Supports Herald Skills, making their triggered effects deal more damage at the expense of higher Spirit cost."

I'm of two minds on this,

the first mind is that it does what it says on the package.

The second mind is that there is no way they'd allow for a runaway reaction chain like that with poison. 30% more damage each time it spreads. it has to be some sophistry like "its not actually dealing damage its just transferring an ailment from one to another, therefore its doing 30% more of 0 damage"

Which is it? Hit G and see if the expanded information clears it up, otherwise we may never know.

The gem info doesn't help at all here. Also, the repeating 30% increase only applies if it the poison is still active by the time the enemy dies, and another is close enough to catch it. I don't think it would be too OP honestly. Contagion and ED already do the same thing pretty much