White Whistle

''This article is about the object. For the delver rank, see White Whistle (rank).''

White Whistles are Second Grade Artifacts that can only be used by their original owner. They are made from ”Your Worth”, the Life Reverberating Stones, and given further shape by the user's own modifications to the stone, making each and every White Whistle unique. White Whistles are able to activate dormant Relics.

The White Whistle is a signature characteristic for the few Delvers that are allowed to delve past the 5th Layer of the Abyss. Currently there are only a handful of recognized White Whistle users, although it is unknown whether or not all of them are still alive.

Life Reverberating Stone
It is revealed by Bondrewd that White Whistles are made out of Second Grade Artifacts, called Life Reverberating Stones or "Your Worth". The raw material required to create a Life Reverberating Stone is a human being. If the person has a firm resolve to sacrifice everything for the whistle's intended user, they can potentially turn into a Life Reverberating Stone. Each Life Reverberating Stone possesses a life pattern unique to the person sacrificed for the stone; the pattern is only compatible with the individual the Life Reverberating Stone is intended for. Hence, the White Whistle can only be used by them.

Some form of consciousness of the sacrificed person remains within the Life Reverberating Stone; as seen when Riko, Nanachi, and Reg found Riko's stolen White Whistle being altered by a Narehate, but Riko stopped Reg from taking it back, sensing that Prushka "did not hate it". Prushka was also seemingly still able to communicate with Riko in subtle signals, as seen during the Fuzosheppu crisis. Furthermore, Faputa was also able to communicate with Prushka to an extent.

Life Reverberating Stones have the strength to pull out the true purposes hidden within certain Artifacts, as seen with the curse-warding box and the elevator leading into the 6th Layer.

In the finalized form of a whistle, Life Reverberating Stones are able to heighten the output of artifacts or beings like Reg. However, doing so will put a strain on the user, which grows more intense and damaging to their health with short intervals between usage, ranging from exhaustion to passing out from exertion. In addition to relics, Juusou are also capable of being released by the whistle.

Thus far, the only individuals known to have Life Reverberating Stones created from them are:
 * Doni, whose stone was used for Lyza's White Whistle.
 * Bondrewd, whose stone was used for his own White Whistle.
 * Prushka, whose stone was used for Riko's White Whistle.
 * Tiare, whose stone was used for Aki's White Whistle

White Whistle Owners
There are only a few known people who own or have owned White Whistles:
 * "The Sovereign of Annihilation", Lyza the Annihilator
 * "The Immovable Sovereign", Ozen the Immovable
 * "The Sovereign of Dawn", Bondrewd the Novel
 * "The Sovereign of Mystery", Srajo the Obscure
 * "The Sovereign of Guidance", Wakuna the Chosen
 * Riko
 * "The Sovereign of Phantasms", Aki the Unseen

Trivia

 * Currently, Riko is the only person known to be in possession of more than one White Whistle; her mother's was passed down to her after it was brought up to the surface by Hablog, and Riko's own White Whistle which she obtained at the end of the Lord of Dawn Arc following Prushka's demise and subsequent transformation into a Life Reverberation Stone.
 * A White Whistle recovered after its owner's death or Last Dive is traditionally given to their surviving family or descendants. If it is declined or the Delver has no living relatives, the whistle becomes property of the Delver's Guild and is kept at their headquarters in Orth.
 * Only a part of the Delver Guild and the White Whistle Delvers know the exact location where the Life Reverberating Stones are usually embellished into their finalized state as whistles. There is nothing on the surface that looks like it, and according to a theory, the place where it can be processed is in the Abyss.
 * The consciousness of a person becoming a Life Reverberating Stone stays intact within the respective stone and is able to communicate with its respective owner on a subconscious scale to the point of holding full discussions with them. They are also able to share senses with their owners to experience events as well as even taste food their owner consumes. There are apparently also other beings able to communicate with any Life Reverberating Stone to a certain extent as shown by Faputa being able to do so.