The Lost Arts (ロストアーツ, rosuto aatsu) are a set of spells cast through particular quartz created during the Dark Ages that consist of multiple septium gemstones. Their enormous powers comes at the cost that each quartz makes use of three elements. Thanks to similarities in orbal wavelengths, the Lost Arts can be cast inserting the corresponding quartz in the ARCUS. It can only be inserted in a element-locked slot that corresponds with one of the three elements of the quartz.