About the creature: Took a walk with the kids today down by the stream. Despite the cold weather it was a refreshing break from everything going on. While walking through the woods, I noted several very obviously dead trees. These trees, despite being dead seemed entangled by the living trees around them, as if locked in a struggle. What you see below is the result of that one small walk.
“Dangerous as they may be, boy, the Fallen Treants are a sight that nearly made me weep. Couldn’t tell you the how or the why of them, but seeing those who used to be the protectors and sages of the land as wasted and unknown … it’s a sad sight. Almost a mercy to be putting them down.”
Hit Dice: 2
Armor Class: 6 
Attacks: Strike (1d6)
Saving Throw: 16
Special: Fallen Blight, Bull Rush
Move: 3 [15’]
Challenge Level/XP: 3/60
Fallen Treant: HD2; HP 15; AC69; Atk Strike (1d6); ST 16; MV 3 [15’]; Al Ch; CL/XP 4/120; Special Fallen’s Blight, Bull Rush
Fallen’s Blight – The Fallen Trent has a 45% chance of being able to infect up to three dead tree or Treant within half its move range. If successful the target becomes a Blighted Wood.
Blighted Wood: HD <1; HP 3; AC 9; Atk Bash (1d3); ST 19; MV 1 [ 5’]; Al Ch; CL/XP A/5; Special Nil
Bull Rush – Once per encounter the creature can make a headless rushing attack that takes the creature its entire movement length at 3x normal speeds to slam into the target dealing 2d6+1 for every 5 feet moved.
In the early days of the world, the Treants came to the forests and the woodlands of Eira. Not of Eira, but not of the Fae Realms, the Treant took it upon themselves to guard and nurture the wild lands. Then the blight came.
A sickness ravaged the wood of the world, killing the trees and the planets, corrupting the land and the creatures within it. The Treants strove to contain and to destroy the blight. They failed, for how where they to known that the blight was of the Fae; fallout of the war between the Au-Sidhe and the Un-Sidhe.
For a long time the Treants remained immune to the blight, their magical nature of being of neither the Mortal nor the Fae Realms protecting them. However, it did not last forever, and when the blight struck the Treants, that nature which had protected them for so long became their greatest down fall.
While the blight killed things of the Fae and Mortal Realms, it did something much more horrible to the Treants. At first it seemed that the Treants to would die, but then those Fallen Treants would rise, their former caring and protective nature gone, replaced by a nearly mindless need for destruction.
The Treants nearly all fell to the blight, but it was not to be as an alliance was made with the mortal fae, the Pixies, whose magic was great, and the tide of the blight was destroyed … at least in part.
Still now in the present, the blight will emerge at random and while both Pixie and Treant fight against it some still Fall …
Fallen Treants can be found in any forest or wetland in the world; however, they are most common in temperate climates, were the ancient blight can thrive. Fallen Treants are, however, rare as healthy Treants will typically put down one of their fallen brothers out of both respect and a need to protect the forest and land from the Fallen Treant’s infection.