Olkari Cubes were introduced by Coran in season 2 of Voltron: Legendary Defender in the episode Greening the Cube as floating cubes from Olkarion, echoing everything one says to the cube. In the episode, Commander Branko forces the Olkari with their capability to create powerful devices out of blocks of steel to create one gigantic cube as a superweapon to destroy Voltron.
Later in season 2, in the episode Stayin' Alive, Olkari Cubes are also used as a communication device between Allura and Coran, as well as between Slav and Coran. The depiction of the Olkari Cubes in season 2 is the premise of the game «Voltron: Cubes of Olkarion». In the game’s story, emperor Zarkon forces the Olkari not to create just one single cube, but various cubes with versatile capabilities to destroy the Voltron coalition.
"With just a wave of their hands, they could build a computer inside a block of steel."
—Allura in Greening The Cube
"What is it?" "Uh, hello? It's a floating cube! Oh, this guy."
—Lance and Coran in Greening The Cube
"There they are! The Olkari Cubes!"
—Coran in Battle Scars
"She used a Robeast to steal the Olkari Cubes, which can mimic and intensify energy at a distance."
—Allura in Battle Scars
Olkari cubes in video games
The Olkari cubes are a main element in the official Voltron video game «Voltron: Cubes of Olkarion». In the game, the player places Olkari cubes of different types and capabilities in a game-board grid and player activate them with mouse clicks. Olkari cube capabilities include fire balls, frost beams and anti-gravitational fields.