Talk:FUG/@comment-103.21.170.130-20161016213145/@comment-5693502-20161016223626

That depends on the context of the word "sleep". Under the assumption that the term "sleep" is synonymous with inactivity and/or even being off-the-radar, then there are a few reasons that spring to mind: Considering 5 of them apparently have unknown whereabouts, these potential reasons are plausible.
 * Generally staying out of sight of the 10 Families (or even a Floor Guardian)
 * Recuperating from a serious/chronic injury
 * Secretly spreading the influence of FUG by converting or finding new members
 * Training to increase their power
 * Some may have even hit a power plateau whilst training and are merely waiting for the right time to strike

All that said, if they really are just sleeping then it's probably because they're waiting for something...