Hatsumōde

Hatsumōde (初詣) was a shrine tori that led to a strange Chaos Zone.

Background
The Shiramochi-ōwas gateway to a special area where the entire Fake Nazarick was turned into a new world.

Mass for the Dead Arc
Momonga having stepped out to the 1st Floor of Nazarick to receive Solution Epsilon and the protagonist explains to them of the strange New Year mood affecting those in Nazarick. To be on the safe side, they decide to recall everyone from outside of Nazarick. The only ones left that seem to be missing are just Cocytus and Narberal Gamma. Their last known appearance was at Fake Nazarick. There, to their surprise, they find what seems to be the Hatsumōde that leads to a strange Chaos Zone. Upon entering the tori, the group finds themselves in the interior of Fake Nazraick that has been converted into a misty desolate desert. While traveling through the strange area, they greet various characters that have been affected by the New Year phenomena. After Momonga and his comrades defeated Shiramochi-ō on the 10th Floor of Fake Nazarick, the tori vanished.

After Shiramochi-ō was defeated, the Ruler of New Year, was reborn in another dimension, one that was similar to the previous world in which he was defeated but had yet to experience the New Year event he caused. His old body crumbled, creating the new personality of Shiro, whilst fragments of his power scattered into the forms of several items. Subsequently, his emergence caused the "New Year mood" that afflicted the NPCs of Nazarick to celebrate New Year. The mental influence compelled all but one of the Pleiades to head over to the Hatsumōde alongside Cocytus to serve as it's guardians in preparation of the New Year event. Likewise, this was after Shiro had collected all his memories from the scattered relics, and revealed that he was the Last Boss of the event. Once he was killed by Momonga as an act of mercy, the Hatsumōde and its area vanished.

Layout
A Japanese stone tori located on the 1st Floor of the Fake Great Tomb of Nazarick. It is decorated with a gold dharma wheel at the top, with lengths of shimenawa wrapped on either supporting pillars. In the middle of the tori is what appears to be an amethyst dimensional gateway which serves as an entrance to the converted Fake Nazarick.

Trivia

 * According to the literature read by the protagonist, the Hatsumōde is the first temple to visit during the New Year.