Dimensional counterparts

"The phrase recited before the Japanese opening themes for the Yu-Gi-Oh! ARC-V anime, during the Heartland City arc."

- The world is divided into four dimensions. In them there are four boys with the same face. The dragons they have call for each other. As if seeking out each other...

A dimensional counterpart is a phenomenon featured in the Yu-Gi-Oh! ARC-V anime, in which a person from one of the Four Dimensions resembles another person from another dimension. In addition to sharing the same face, the counterparts seem to be drawn to each other. Yuya Sakaki and Zuzu Boyle are the only characters to have dimensional counterparts.

History
Yuya and his counterparts are the reincarnations of Zarc while Zuzu and her counterparts are the reincarnations of Ray Akaba, who came to be when Ray used the four cards created by her father, Leo Akaba, to split the Supreme King Dragon Zarc with herself and the United World, which resulted in the creation of their reincarnations and the Four Dimensions.

Leo eventually regained his memories of the events, and he attempted to recreate Ray by capturing Celina and her counterparts. He had Yuri, Zarc's Fusion fragment capture Lulu Obsidian and Rin for him, and later sent him after Zuzu Boyle. These actions caused Yuri and his counterparts to come in contact with one another, and Yuya Sakaki accidentally absorbed Yuto after Yugo defeated the latter in a Duel, resulting in Zarc's influence driving his fragments to desire to become one. Declan also believed that Yuya and his counterparts were also involved in Leo's Arc Area Project due to Yuri and Celina being involved in Revival Zero.

Mistaken Identities
A common recurrence is for a character to confuse one counterpart with another counterpart due to their identical facial structures. Instances of confusion include:

Yuya Sakaki
Yuya was the first character to have a dimensional counterpart. These counterparts each have a Dimension Dragon, can enter a rampant state of mind, and sync with each other. If a counterpart has absorbed another into his body, the one absorbed can possess the other's body. Each of Yuya's counterparts served as secondary protagonists of the series, except Yuri who was a major antagonist. They have currently become one and revived as Zarc.

When all four of them are Awakened and their Dragons are Summoned, they chant in unison about merging into a single being. They are Zarc's reincarnations.

Zuzu Boyle
The second character to be known to have dimensional counterparts was Zuzu. Similar to how Yuya and his counterparts each possess a Dimension Dragon to help signify themselves as counterparts, Zuzu and her counterparts each wear a bracelet, which have mysterious abilities. For this very reason, they are collectively called Bracelet Girls (ブレスレットの, Buresuretto no Ko).

Zuzu serves as a secondary protagonists of the series with Celina, Rin, and Lulu each playing a major supporting role being her counterparts. At one point, they were all controlled by the Doktor's Parasite Monsters, making them temporary antagonists, however, they were finally freed when the Professor carded the Doktor for his dangerous thinking. They have currently been absorbed into ARC-V.

The girls' decks are shown to each have a feminine themed to them as nearly all their monsters are female. Their decks also possess a synergy to Fusion Summon and each one is based around a natural beauty. They are Ray Akaba's reincarnations.