The Dreamworld, also known as "The Dreamland" (And refered to by our team as "Macroprosopus") is a place where the soul can have whatever the mind can imagine. Linked to the phisical realm by unknown reasons and means, this place is where our souls create it's own world and reality, duplicating people and objects they know to archive an ideal reality or a terrible nightmare. When the soul in question is an alive soul, a soul with body, it changes and takes shape on the mind's state, that is why the dreamworld is always diferent. A theory states that the dreamworld is also the Afterlife. That when the body of a soul dies, the soul absorbs the mind, taking the final form a soul shall have. This form is also the "Awaken soul" that will live forever. The dreamworld is not our reality though, and everything inside it is destroyed when the dreamer wakes up. EXEPT the dreamer was never in it's own dreamworld to begin with. There are some cases in which the soul goes without knowing to the collective subconscious, a place that can be described as a vast space in which all souls coexist at the same time. Other times, the soul visits another's dreamworld, but some other times... the soul ends up somewhere else. We don't have a word for this place. It is like the collective subconscious but only a certain number of people can exist in this place at the same time. And they are not in control of this place. Souls that go here are not aware of this untill they find something strange and force their body to wake up. For reference, we call this place Tartarus (But keep in mind this is not an official term)
There are nightmares and Dreams, but in the dreamworld, all of that is "Real".
The dreamers that have seen the Slenderman have ether created a perfect Replica of the Slenderman in the Dreamworld that is destroyed upon awakening, or have finded the real one in Tartarus. Why is slenderman there? We believe that he goes to many realms and dimentions at will, the Dreamworld is one of many. He stalks the souls in the Dreamworld just as he does to our world, the diference is, in the Dreamworld, we can dissapear and even fight back. Maybe he does not understand the diference between the dreamworld and the other realms as he seems to stalk some people exclusivly in a realm and not in both. It's possible there are many of him/it, but we can't be sure.
Slenderman is a dimentional being, he is capable of entering all the realms and dimentions known to human (6 Realms: Microprosopus (Our Realm), Dreamworld (Macroprosopus), Atziluth, Briah, Yetzirah and Assiah) and he is also capable of surviving in all of them. It is known that he moves freely between these realms. Why does he stalk people only at one realm? We don't know.
Slendeman inhabits the Dreamworld like he inhabits the other realms, but he is not nearly as dangerous in the dreamworld as he is on reality. Humans are phisical beings bounded to our world, a dimentional being such as slenderman can and will cause harm to every being that is bounded to our realm, because we can't go elsewhere. Slenderman is only dangerous to humans in the phisical realm, and not in the Dreamworld. Even if the real slenderman does operate in the Dreamworld, he represents no danger at all for the dreamers.
As always, I Beg for corrections, suggestions and observations.
Personal note: This investigation has been the most dificult one, I'm sure we made a mistake somewhere. It was also our first team investigation. Most of this entry is based on analysis and deduction, Nothing is a fact in this entry. Take it, or make your own assumtions. Thanks for taking the time to read.
The next subject will be about a complicated subject. We will try to make the entry before 20th. Next subject will be about "Knowing him/It". If things go smoothly, the entry will be posted on this same year on Dicember 15. I'm not part of the main investigation so I'll upload some knowledge about the realms in the meantime.