Class (クラス Kurasu) is a property of SIGNI. Classes do not have inherent rules or abilities, but many card abilities only affect SIGNI with a certain class. A SIGNI class tends to generalize the theme of SIGNI belonging in that class.
A SIGNI's class appears at the bottom right corner of its card art, to the top right of its actual card text.
The names of classes are separated into two parts like a taxonomic rank; often a general type of "Spirit", followed by the more specific "race." Because of the broad, color-crossing nature of referring to SIGNI classes by their Spirits, SIGNI classes generally refer to the more specific races of SIGNI that are generally unique to a single color.
Occasionally, SIGNI will appear in a color that is not the typical one for their class. Before WXK-P01 Klaxon, these SIGNI were marked with special symbols around their name, and their kana reading has a word added to it.
Holy (ホーリー Hōrī)
Blaze (ブレイズ Bureizu)
Smart (スマート Sumāto)
Wild (ワイルド Wairudo)
Fallen (フォールン Fōrun)
Currently, the cases of SIGNI not appearing in their typical color are: