Aki and Toru's childhood friend. Tokiya is the president of Science Club and former commander of GD. Shuri's weapons are designed by him.
Tokiya had been hikikomori during half a year since he lost Aki. Because he could not keep living in a world without Aki, he made a contract with Hiwako and became an Asura Cryin' after stealing Hagane. He intends to use the Hagane's time-space manipulation powers to create a 3rd Stage World and start everything all over again.
Using Hagane's power, Tokiya gains Hisui, Bismuth, Rhodonite. Using all 4 Asura Machina he gained, he make Central Vortex gone out of control to start the destruction of the Second World. After gate to the Third World opens, he goes into the Third World with Hiwako.
After realizing that Third World wasn't the world he imagined, he seek to take Igniter from Tomoharu's party in order to create the perfect world he dreams of and clashes against Tomoharu's party to create that perfect world even if it means to destroy every world including First World, Second World, and newly created Third World to create that perfect world.
After Tokiya and Hiwako got defeated by Tomoharu and Kanade, Tokiya lost will to live. He is currently in wheelchair and aided by Toru.

(First World)

Freeloader who stays at Kitsutaka house. Tokiya from First World explains to Tomoharu from Second World about experience Naotaka from First World are involved in and discuss what had gone wrong. He's very clumsy but he receives lots of jobs to research things from all over the world according to Toru. Tomoharu muses that if Aki was here in Second World, maybe Tokiya wouldn't do what he did in Second World.

-Wikipedia-