Fudaraku has the ability to stockpile sword energy and its cost is the time required to do so. While the Orga Lux is in its sheathe, it continues to absorb power from its wielder, increasing its power and sharpness. Although there isn't a limit to how much it can stockpile, the user may become unable to control it if the amount goes past a certain point. Fudaraku becomes dull after one use, therefore the user has to charge it again.
According to Claudia, stockpiling for a month would be enough for Kirin to fight using Fudaraku against Ayato wielding Ser-Veresta.