Syncryptoid

undefined:

A group of partially hidden headmates who all are related to each other in some way. Could be a subsystem, sidesystem, cluster, or any type of group within the system. They could be hidden to the whole system, to certain parts of the system, or from people outside of the system. They could also have no physical appearance and may not show up in the headspace.

They may or may not be aware that they are hidden, and there could be a reason (conscious or subconscious) behind them being hidden.

Related Terms
A cryptoid is an individual member of a syncryptoid.