According to the Wisewood, the Plague Fly that live near them is the main vector for the plague.
The wisewood can't infect each other and the Plague-Eater Worm that Agatha mentioned is not the main vector either.
She had underestimated the ability of the Plague Fly.
The plague is carried by the Plague Fly and spreads itself through their habit of biting things.
The Wisewood explained further.
This is why the plague has lasted for so long here. The plague you see today is almost identical to what was spread by the Necromancers.
* Once quest is complete, read this book to report back
I feel better after eradicating some of the plague-carrying insects.
I had at least tried to make up for our past mistakes a little.
At least I knew the truth behind this event at last.
The Wisewood pleaded with me to bring clerics to treat the surviving wisewoods, as they told me, otherwise when the insects suck on our sap, they will start spreading the plague once more.
I immediately promised the wisewoods my help.
As I left the Plague Forest, I held Yab's hand and thought about everything that I had experienced.
I now know the reason for the unfriendly skeletons, the endless sorrow within the tears, the dire howl of the wolves and the fearful look in the wisewoods.
The inscriptions on those old tombstones were the true history.