Core Brick Mode (Japanese: コアレンガモード, Koa Renga Mōdo) is a mode where a Quartonian is in the form and shape of a brick. When the boys go through the portal in Mr. White'sshop to Quarton, their core bricks unfold and they transform into the legendary Tenkai Knights. Beag and the Corekai soldiers use this mode to assist and protect the Knights. Corrupted soldiers use this mode to protect higher authority of the Corrupted and become an obstacle for the Knights and to trap them. When the Guardians battle the Knights, they use Guardian Megafusion, which consists of Corrupted members and themselves as core bricks.
In Tenkai Knights: Origins, Core Brick Mode would mean that the Quartonian is defeated and has no more Tenkai Energy. However, in the actual show, if the Knights have no more energy, they are transported back to Earth. If a Quartonian was defeated, they would explode as small cubes.