Yo-kai Arks

A **Yo-kai Ark** (**妖怪アーク**, **Yōkai Āku*, Yo-kai Keystone*) is a small, key-shaped item used to summon Yo-kai from the Yo-kai Watch Elda. They first debuted in M04 and the Shadowside anime, and would later appear in *Yo-kai Watch 4* and *Yo-kai Watch!*.

They are said to be the successor of Yo-kai Medals, with some of them featuring Lightside and Shadowside Yo-kai on both sides, while several Yo-kai either have nothing at the back or a Onechanside until it was removed. Rare variants with different colors also exist.

Just like with Medals, Yo-kai Arks have been made into real life collectable merchandise. The levels of rarity that range from common, to extremely rare, are Normal, Rare, Extreme Rare, Super Extreme Rare, and Ultimate Rare. Most of the Normal Arks have a clear color and a regular holo foil, while Rare Arks have a clear color and a glittering holo foil, and Extreme Rare Arks have the colors of their tribes, as well as glittering holo foil. There are also Shining Arks that are equal to Super Extreme Rare ones, and Gold Arks that are equal to Extreme Rare ones.

There are 330 Keystones in total.

## Overview

Yo-kai Arks represent the feelings that connect Yo-kai and humans. Just like Yo-kai Medals, they are given to select people once they fulfill a specific Yo-kai's needs.

Yo-kai can be summoned via the Yo-kai Watch Elder by putting the Ark into the keyhole, and saying the summoning chant while the Yo-kai appears in sight.

It was originally thought that the Arks were successors to the medals, but due to their inclusion in Forever Friends and Yo-kai Watch!, they existed in the past and present as well. However, in *Yo-kai Watch 4*, Nate's Yo-kai Medals turn into Arks after he visits the future world, probably due to the effects from the future which is why the Arks are truly the Yo-kai Medals' successors.

## Types of Arks

**"Yo-kai Arks" is a title based upon conjecture.**

### Shadowside Arks

Shadowside Arks are ones that apply to Lightside and Shadowside Yo-kai, with both of the sides representing the Lightside and Shadowside form. They appear regularly throughout *Yo-kai Watch Shadowside*, and in the future world of *Yo-kai Watch 4*.

Merchandise-wise, several Keystones have different variants of existing Yo-kai, such as Junior's Shadowside form taking the form of Blizzard Wolf rather than Burning Dragon, and Nekomata's Shadowside Gold Ark being of an unidentified entity.

### Godside Arks

Godside Arks function just like Shadowside ones, except they have a third form which is considered to be stronger than their Shadowside. They were first featured in M05, where Yo-kai like Nekomata, Zashiki-warashi, and Kappa are given forms after they were summoned with the Yo-kai Watch Elda God.

A few of those Keystones appeared in two of the Yo-kai Ark Zero series sets, which are colored white instead of light-blue. Though, Yo-kai like Yamambaa and Suu-san have differently-shaped Arks.

### Onechanside Arks

Onechanside Arks are used for regular Yo-kai that have appeared in the original games and anime, and serve as a replacement for Yo-kai Medals. They are used prominently in the Yo-kai Watch! series, where Nate uses them to summon them in the same vein as he usually does.

Regular Arks at the back have a background, with the silhouette of the Yo-kai present. While several Yo-kai now has a "Onechanside", which allows it to take on a different form that could drastically change any outcome.

## Merchandise

*Main Article: List of Yo-kai Keystone Sets (Japanese)*