The Outside

"This is the outside of... well, everything."

- Azazel

Ein Sof, or The Outside, is the utmost divine and most primordial realm that ever exists, locating outside of Creation and emcompassing it in its totality. It is beyond the Four Worlds and is often described as the crown of the Adam Kadmon.

Summary
Ein Sof is the utmost divine and most primordial world that was formed when the Celestial Princes were created by God, as the celestial power they radiated accidentally given form to it amidst the primordial void of Tehom. Despite this, Ein Sof neither is or isn't an Olam (עוֹלָם‎; "world" or "eon"), as such a term cannot be applied to it.

In this world, concepts such as duality, space, time, finite, infinite, life, death, existence, or nonexistence are absolutely meaningless, nullified by the very presence of God and can only a "maybe" or "perhaps" as dictated by either God or the Princes themselves.

It is a world beyond time, space, void, fate, and death, freed from all restrictions and constraints that are within the core of Creation, even in the Four Worlds and Adam Kadmon. It is the collective unity in the background, lying beyond Creation which is merely an infinitesimal blip within its entirety. It is also known as "The Outside" and "The Realm of Everything and Nothing", as it was in this world that the concept of nothingness manifests.

And yet, despite all of its titles, Ein Sof cannot be described as a world or a realm, for it exists on a level of existence greater than such simple definitions.

Realms

 * Shamayim: The first realm of the Ein Sof, created by God to be the home-realm for Him and His angels. This is also where the souls of those who have died the utmost righteous and virtuous deaths will ascend to, living in absolute happiness and bliss for the rest of eternity as rewards for their fruitful life.
 * Sheol: The second realm of the Ein Sof, created by Lucifer to be the new home-realm for him and his demons following their banishment from Shamayim as punishment for the Heavenly War. This is also where the souls of those who have committed the utmost despecable sins and crimes in their life shall be dammed to, living in endless pain and subjugated to punitive sufferings and torture for the rest of eternity as punishment for their sinful life.
 * Purgatorium: The third realm of the Ein Sof, created by Samael to serve as his and the Grigori's main base of operation, as well as the new home-realm for the fallen angels who were banished from Shamayim. This realm also serves as an intermediate state after one's physical death for expiatory purification, where a soul who dies virtuously but still imperfect will be purified to achieve the holiness necessary to achieve Shamayim.

Quotes
"Any name of God which is found in the Bible can not be applied to the Deity prior to His self-manifestation in the Creation, because the letters of those names were produced only after the emanation... Moreover, a name implies a limitation in its bearer; and this is impossible in connection with the "Ein Sof"."

- Minḥat Yehudah

"Before He gave any shape to the world, before He produced any form, He was alone, without form and without resemblance to anything else. Who then can comprehend how He was before the Creation? Hence it is forbidden to lend Him any form or similitude, or even to call Him by His sacred name, or to indicate Him by a single letter or a single point... But after He created the form of the Heavenly Man, He used him as a chariot wherein to descend, and He wishes to be called after His form, which is the sacred name "YHWH""

- Zohar

Trivia

 * The realm is implied to possibly be older than the Princes themselves.
 * Gabriel stated that it was God's gift to them, being created in celebration of their creation.
 * Uriel once said it was for more older than them, with possibly the exceptions of Michael and Lucifer, and might be as ancient as God Himself.
 * The realm is implied to possess some form of consciousness.
 * The Ein Sof could be likened to the library of which the shelves of Adam Kadmon are contained.
 * Ein Sof in Kabbalah is the state God was in prior to self-manifestation. The term was first used by Azriel of Gerona, one of the most important Kabbalists at that time, who held Neoplatonic beliefs and thought that God can have no thought, no desire, or action as all of these are negated by it. It is the origin of the Ohr Ein Sof (The Divine Infinite Light).
 * In Lurianic Kabbalah, the Tzimtzum (Self-Withdrawal), which is the first act of Creation, takes place within the Ein Sof to create an empty void from which all of Creation springs from.
 * Ein Sof springs from the concept of Ayin, which is the Nonexistence beyond Nonexistence and Existence and cannot be defined. In the Tzimtzum's order of de-evolution into our physical creation, Ein Sof is defined as 00.