Sea of Possibilities

Sea of Possibilities (可能性の海) is another world where information exists.

Background
According to Shiramochi-ō while he was a product of the wishes of the Seven Lucky Gods, who's story exist in a book from Ashurbanipal, he is also a being derived from that literary work. Though he admits that the story found in the world is a book that originated as data from a place called the "Sea of ​​Possibilities."

Mass for the Dead Arc
The Sea of Possibilities is revealed to Momonga by Shiramochi-ō who explains his origins. In that, he was the data of the desires from the praises of the gods. While his existence was something that was originally impossible, it was made only possible by a mistake resulting in Shiramochi-ō taking shape in the world. Perhaps because of that, there was an inconvenience because in order for it to manifest, Shiramochi-ō needed to include other "New Year" information and make it a part of his body. If not, he would not exist unless he could develop an area dominated by "event"-like rules.

According to Shiro, after he willingly died at the hands of Momonga through [True Death], it was not the end for him. Instead he found himself back in the Sea of Possibilities, this time with all his memories intact. A year had passed in the New World, which at the time a the celebration ceremony from Nazarick at New Year's attracted the attention of Shiro's creators who then sent another version of Shiramochi-ō to act as a raid boss against Nazarick. Shiro not willing to allow his friend be troubled by his copy, and also unwilling to give up his title as the Ruler of New Year, managed to hitch a ride through the summoning and return to Nazarick, this time though to aid Momonga and his friends.

Layout
The Sea of Possibilities from one account is where stories exist in the form of data.

Trivia

 * From the limited description of the Sea of Possibilities, it bears a canny resemblance to the Akashic records" or "Akashic library", an cosmic compendium of all knowledge and history.
 * In a special crossover event, a being known as Eyepatch Kurumi claimed to be a possibility that was a manifestation of unconscious fear. According to her, she was born from psychic energy of the host body, that leaked out of the world and into an location of what could be called the space between worlds. There "something" allowed her to take substance, giving her possibility form and appearance.
 * According to the background of [Crystal Bride] Evileye, the Crack where the Throne of Kings once stood is a passage that connects the New World and the Sea of Possibilities.
 * After learning about the dangers coming from the Sea of Possibilities, Aura Bella Fiora developed aspirations to be a tank like her creator Bukubukuchagama. Likewise Shalltear Bloodfallen wishes to emulate her creator Peroroncino and be a archer. Mare Bello Fiore followed suit and began imitating his creator. As with Demiurge when dressing as Ulbert Alain Odle. And also Yuri Alpha in her outfit as Yamaiko.