Halloween Festival

Halloween Festival (ハロウィン祭) was a holiday game event in YGGDRASIL.

Background
A holiday event that occurred on Halloween in YGGDRASIL. During Halloween, there was the release of a new Halloween themed skin, though it was noted that humanoid ones were cuter.

According to Ainz Ooal Gown, Halloween was based on a European holiday involving the celebration of pumpkin harvests. It later became associated with costumes and candy. From another source, costumes worn during Halloween were to protect humans from horrifying beings that came out during that time. When it comes to Halloween, the image of spirits and monsters is strong. It's noted by the Overlord that it shares similarities to Obon holiday in Japan. Though Halloween was an event that once held a religious significance, overtime it became just a seasonal event.

Albedo and Shalltear Bloodfallen doing research, found various descriptions on Halloween's origins, one being that it was originally a festival to welcome spirits of the past. However the, at the same time evil spirits came, so the living had to wear costumes to disguise themselves as evil spirits to avoid disaster. Though there are accounts where the costumes were worn to scare away demons or that it was a harvest festival.

Purpose of Event
According to the lore, it is a memorial for ghosts. During this time pumpkins are possessed by the spirits of the dead creating Jack-O-Lanterns. These monsters come out and attack players. Since these monsters are a type of undead, smashing them will prove useless, so in order to eliminate them, players must hollow the pumpkins and light flame inside. In doing so the spirit is banished from the pumpkin and the spirit is at peace. The after result creates a jack-o-lantern which can be used as a decoration. As an option players can dress in various costumes during the event and call out "Trick or Treat."

Aftermath
This event was possibly hosted in the game until its subsequent shut down. The details of this event were archived into an event book, titled as "Halloween Festival" and styled as a ritual book. One is found in the Great Tomb of Nazarick in Ashurbanipal and later used to avert a crisis when pumpkin monsters infested Nazarick.

A year later, a rendition of the Halloween Festival was replicated in E-Rantel for the Harvest Festival to celebrate the bounty of the field in the fourth wall. The event was organized by the protagonist who called it "Greetings and Victory" to show the world the culture of the Sorcerer Kingdom. The event served to connect the Boastful Sage and provide a history to the kingdom's origins. And also to use as a lure to attract players that may be lurking in the shadows. After the successful event and deception, Momonga hosted a small Halloween Festival in Nazarick to celebrate.

In the aftermath of the Calamity of Cracks, E-Rantel was once again devasted by a never ending attack of Chaos Beasts and Contaminated Beasts. During the city's recovery, in part to the support of the Sorcerer Kingdom, the human authorities made a request to the non-human nation to host the "Greetings and Victory" Festival to boost morale of the city. It was permitted by Momonga who wanted to spread his nation's influence over the Three Kingdoms.