Ephemer

Ephemer is a Keyblade wielder who appears in Kingdom Hearts χ. He seeks to discover the truth behind the gathering of Lux and the structure of the world. He claims to be in a union differing from 's, regardless of what they choose.

Before Kingdom Hearts χ
At an unknown point, Ephemer is chosen by the Keyblade and joins the Vulpes Union under Ava. Shortly thereafter, Ephemer meets Skuld and joins her party. For a long time, Ephemer and Skuld undergo missions together alone until more wielders gradually join them in their mission to gather Lux. Due to their busy schedules, however, Ephemer and Skuld begin drifting apart, putting a strain on their friendship. Eventually, Ephemer decides to leave the group to go his own way.

Ephemer begins to question the secrets of the world and the Book of Prophecies. One day, Ephemer approaches Ava and asks her why the Unions compete against each other rather than working together, and Ava explains that it is because the Master of Masters arranged for things to be this way between the Unions.

Kingdom Hearts χ[chi]
Ephemer meets while in Waterfront Park, where he is bested by an Invisible, and Player steps in to help Ephemer defeat it. Ephemer introduces himself to Player, and the two learn that they are from opposing Unions. In spite of this, Ephemer reveals that he is investigating the truth behind the Book of Prophecies and why the Unions compete against each other for Lux.

When Player tells Ephemer about a dream of they had the night before, where the Foretellers met with a hooded figure in the Foretellers' Chamber, Ephemer suggests that they investigate the Foretellers' Chamber located in the Clock Tower. Ephemer and Player attempt to sneak into the Clock Tower through an entrance in the sewers, but are mobbed by Heartless along the way and unable to proceed further. Ephemer persuades Player that they should continue their investigation the next day since it would suspicious if their Union leaders notice that they were missing for too long.

Sometime later, Ephemer comes across a depressed Ava sitting alone at the Fountain Square. Ava confides in Ephemer about her doubts about the Master's teachings regarding the competition between the Unions, much to his surprise. Ava approves of Ephemer's desire to solve the mysteries of the world, as she believes that people should question things and think for themselves. Ephemer jokingly tries to get Ava to talk about the Book of Prophecies, but she denies him. Ephemer tells her that he had befriended a Keyblade wielder from a different Union, and Ava is pleased that wielders from other Unions could work together. Before Ephemer leaves, he asks Ava to cheer up, which brings a smile to her face.

Later that night, Ephemer returns to the sewers to continue his investigation alone. Before Ephemer can enter the Clock Tower, however, he is confronted by Ava. Relocating to the outskirts of Daybreak Town, Ava divulges the final entry in the Book of Prophecies, which details the events of the Keyblade War, and recruits Ephemer to join her Dandelions to ensure the future of the light. Ava selects five people from the Dandelions, including Ephemer, to act as Union leaders in the Foretellers' stead after the war. Ephemer is reluctant about becoming a Union leader, but Ava implores him to rise up to the challenge and provides a book of rules that must be followed once the new Union leaders take charge to prevent future destruction. Moreover, Ava informs Ephemer that the Union leaders must erase the memories of the Keyblade War from their fellow Dandelions and avoid any possible connections between the two worlds, thus the truth about the war must be kept a secret among the new Union leaders. In spite of his misgivings, Ephemer accepts this task and is then sent to another realm to meet the other Union leaders in the Keyblade Graveyard following the war.

From this other realm, Ephemer attempts to reach out to Player by showing them his conversation with Ava in a dream. Around the same time, Ephemer also visits Skuld in a dream and tasks her to seek out Player, warning her about the impending war.

When the Dandelions cross over to the new world, Ephemer is reunited with Skuld, who had accepted Ava's invitation to join the Dandelions. They venture back to the Keyblade Graveyard following the conclusion of the Keyblade War and find Player unconscious on the battlefield. When Player awakens, Ephemer happily reunites with Player and convinces them to join the Dandelions. Ephemer and Skuld bring Player to the new world, where Player's memories, along with the memories of the other Dandelions, are erased upon arrival.

Kingdom Hearts Union χ[Cross]
As per Ava's instructions, Ephemer goes to the Keyblade Graveyard and is shocked to learn that Skuld is one of the new Union leaders, as the identity of the Union leaders was meant to be kept secret until they all met after the war. They are soon joined by the third Union leader, Ventus. While waiting for the other Union leaders to arrive, Skuld and Ephemer bond with Ventus, who admits that he is envious of their close relationship because he has always been alone. Ephemer and Skuld assure Ventus that they consider him a friend.

When the fourth Union leader, Brain, arrives, he asks if Ephemer is their leader, and Ephemer denies this, as the decision must be made once all of the Union leaders are present. When the others begin expressing their discomfort with lying to everyone about the Keyblade War, Ephemer thinks about the pain that Player endured because of the war and states that no one else should have to carry the burden of the past.

Later on in Daybreak Town, Chirithy reports to Ephemer and Skuld about Player's persisting nightmares about the Keyblade War. While Skuld encourages that Chirithy to protect Player from the truth, Ephemer mentions that he senses a different darkness that he plans to investigate with Skuld. Once Chirithy leaves, Skuld questions Ephemer's wisdom about telling Chirithy about the darkness, as they likely just made Chirithy worry, but Ephemer argues that it affects everyone. Ephemer mentions that he detects something strange about Union χ, though Skuld reminds him that the rules dictate that they lead the Union χ.

Kingdom Hearts III
Ephemer aides Sora in defeating Master Xehanort's Heartless cyclone at the Keyblade Graveyard.

Design
Ephemer has curly, silver hair and blue eyes. He wears a white shirt under a black vest with grey accents, dark grey pants, and black boots. He has a red scarf around his neck. Ephemer wears a tan pouch around his waist.

"" refers to things that are short-lived or transitory.

Abilities
Ephemer wields the third upgrade of the Starlight Keyblade.