Eons ago, a cube-like peaceful planet named Quarton, populated by shape-shifting living bricks called Tenkai, was ravaged by a war between two opposite factions: the Corekai Soldiers, led by the valiant and fearless Commander Beagle ("Beag"); and the Corrupted Army, led by the ruthless Lord Vilius, who desired to obtain the source of Tenkai energy for his own purposes. However, the only ones who were strong enough to defeat him were the Legendary Tenkai Knights of Quarton: Bravenwolf, Tributon, Valorn, Lydendor, Dromus, and their lovable but fearless female member of the team Venetta. Facing defeat, Vilius unleashed the mighty Tenkai Dragon, who was later defeated by the six Knights, its fragments scattered across the planet. These heroes were never seen again, but now, a year later, Lord Vilius and the infamous Corrupted Army have returned, more powerful than ever before.

Now, on planet Earth, in the year 2034, within Benham City, five young teenage boys Guren, Ceylan, Toxsa, Chooki, Gen and 1 beautiful but mysterious girl named Beni find an interdimensional portal to Quarton where they are chosen by Boreas of the Guardians to become the new generation of Tenkai Knights and prevent Lord Vilius and his Corrupted Army empire from taking control of both worlds.

Source: Wikipedia

Note: The series premiered on Cartoon Network in the United States in August 2013, in Japan the series aired from April 5, 2014.

AniDB | ANN | MAL | TVDB | Wiki (en)