Barian World

The Valian World (ヴァリアン界, Varian kai) is an unknown world suggested to be a counterpart of the Astral World.

Orbital 7 has a gem that fuels him with Barrier Light, an unknown fuel that comes from the Valian World. Kite Tenjo also mentioned it when he confronted Astral, and said it has something to do with his reason for hunting "Numbers".

According to Tron, the Trap Card "Angolmois" is able to open the doorway to the Valian World. When it did so in III's Duel against Yuma Tsukumo, the gateway threatened to destroy all of existence. However, III and Yuma worked together to close the gate.

Etymology
The Valian World is referred to as "ヴァリアン界" ("Varian kai"). "Kai" is typically used with "Sekai" to mean world, but it can also refer to a barrier, boundary or seal. Oppositely, Astral's home is referred to as the "アストラル世界" ("Asutoraru Sekai"). "Sekai" more generally means the World proper, and/or the Universe.