The Infected Forest

I have encountered many biomes before, but none like this.
One of the three that were hidden deep in The End, it was a haunted place known as The Infected Forests. The end stone was covered with a red, drooping grass, and infected bats fluttered about. The place was filled with strange trees, and a red-bricked dungeon ran as an underground network.
The moment I entered the forest, I felt a slight weakness to my knees. I knew that it was the infection that The Infected Forests gave me, however I had a remedy for it. I produced a sludge-filled glass bottle from my side and took a sip of the goop. The weakness instantly subsided and I continued.
It wasn't long after when the infection occured again. This time it was much, much worse, causing a swelling pain in my knees and a massive internal pain in my lungs. I choked down more of the remedy to stop the pain, but I knew what would come eventually. The Infected Forests only gave me a bit of the infection, but the remedy was really a drug; if I ingested it, the infection would subside, but when The Infected Forests gives it to me again, it feeds off of the remedy and increases in worseness, as a terrible aftereffect. I knew that I shouldn't spend too much time in this forest, but I needed to get a knowledge note hidden somwhere in it. I couldn't leave just yet.
I continued towards a cave, and a large swarm of infected bats burst out of the cave and fluttered out. When they left, I could feel the infection, back again. This time, I felt the swelling pain in my brain, and I had a massive stomach ache. My arms and legs felt like they were straining against a tremendous weight. I drank what was left of my remedy to cure it and continued.
I found the entrance to the red-bricked dungeon and entered it. I found a room with many chests and began checking through them. Dragon Essence... Eyes of Ender... pieces of paper? Why do they even have these?
I felt the infection strike again, but this time it was like a hammer. My whole spine convulsed hard, the vertebrae detatching, and my lungs tied themselves up in knots.
Screw the knowledge note, I thought. I've got to get out of here before this place kills me.
I made it back to the surface, but right then, my legs stopped working and I collapsed. I felt like the bone marrow was being eaten away from the inside, and the pain was incredible. I struggled to move, but couldn't.
Then, I saw the figure. It wore green armor, including a helmet that covered its face. It towered at least 4 blocks in the air, and its legs were bent in a zig-zag shape like an animal's, and tapered with sharp claws. A long, black tail swished around behind it, and it seemed to have dragon wings, though they were hanging downwards, trailing on the ground, like a cape. In its black claw, it clutched a scythe, the rod of it pale as the end stone and the blade a shimmering purple.
The figure walked up to me and stopped. I looked up weakly and saw that it was staring down at me. It gripped its scythe in both claws and raised it above its head. And as it did, two things ran through my head. The first was, is this Death? Is this what Death looks like? A tall, green-armored figure with wings and a tail? He seems to fit the role well enough.
The second was the scythe itself.