They can be seen attached on the shell of the Black Shinkansen most of the time. When the Black Shinkalion approaches its target, huge amount of the particles are released from it and cover up the target. After that, they can reform the target into a Giant Monsterous Being.
According to Iza in Episode 64, LuxVitae supports the entire Underground World. When the LuxVitaes are gone, all of the Kitoralsus buildings would collapse.