Hallow's End is an annual festivity that takes place in late October that is celebrated across Azeroth by many races and cultures. During this time of year, it is a common tradition to wear costumes varying from witches to skeletons and give treats to children who go out "trick or treating" while costumed.
For humankind, Hallow's End was believed to be a time when the barrier between the living and the dead was thin, and those who had passed on could be sensed by those still alive. Traditions often varied between the kingdoms. For example, in Lordaeron, tradition had it that near the end of harvest seasons a wickerman was erected outside the royal palace to be lit on fire at sunset on the night of the ceremony. Anyone who wished could approach the burning effigy and toss a branch into the flames, metaphorically "burning away" anything they did not wish to carry into the quiet, deep reflection time provided by winter’s enforced inactivity.
The practice of burning the wickerman went forgotten for a time after the fall of Lordaeron and the end of the Third War, but the humans of the Alliance continued to hold their traditional festivities, even though they didn't understand why, in the hopes of a brighter future despite the countless losses of the great wars against the Horde and the Scourge. In the wake of the Cataclysm, the Gilneans returned to the Alliance, bringing with them a deeper understanding of Hallow's End's origins and reintroducing the practice of burning the wickerman, which they place just outside the gates of Stormwind City. For the Gilneans, Hallow's End is considered a crucial time for ritual and for shedding burdens. After the Invasion of Gilneas, the practice of remembering the fallen as they cast away their burdens has gained more fervor so as to not forget the lessons the past has taught them and to revere those who have passed on.
Following the end of the Third War, the undead people of Lordaeron continued the celebrate Hallow's End, not as a time of renewal or reflection, but to mark the day they broke away from the Lich King and regained their free will. They burn the wickerman to honour their Queen and as a symbol of their struggle against those who would oppose them, and smear its ashes across their face as a symbol of their neverending fight against those who would enslave them.
Since the end of the Third War, festivities have been disrupted daily by antics committed by the opposing faction, usually involving stink bombing an enemy town. The town of Southshore and the outskirts of Lordaeron City were usually the targets of these antics, but Stormwind instead became the target of Horde interference after Southshore was plague bombed. Additionally, the cursed paladin Thomas Thomson, more commonly known as the Headless Horseman, is known to routinely attack Alliance and Horde villages during the course of the festivities.
With Gilneas' reinclusion into the alliance, the festivities of Hallow's End have changed from a mockery of the Forsaken celebration to that of its original intention, the abandonment of regrets and shedding burdens as well as celebrating the harvest season. While deeply rooted in druidic ritual, Hallow's End has been adopted as transcending the Old Ways; as many look to the celebration as one of healing and happiness rather than purely just obscure ritual. Children often decorate themselves in fanciful costumes, as well as some adults, and partake in handing out confections or various sorts of well-mannered pranks and the like.
Gilneans have been known to take the holiday very seriously. While partaking in the aforementioned newer conventions, the Gilneans often couple the celebration with burning the Wickerman as kingdoms did in ages past as well as hosting elaborate feasts or festivals to accompany it. While the Kingdom has fallen into disrepair, the current king, Genn Greymane, has continued these festivities in the city of Stormwind. The Duchy of the Ashen Coast has also gone about continuing the festival, with their annual Gilnean Hallow's End Festival.