Soulbond

undefined: A soulbond is, broadly, a member of a system or a presence in someone's mind that is a fictional character in some way.

It is commonly used to refer to a walk-in from another world that existed independently from them before arriving, or holds the metaphysical belief that they did. It may also be used to refer to a fictive that takes a separate sentience, especially among writers. It can also be a connection one feels to a fictional character to the intensity that they appear in their headspace or as an internal voice.

Related Terms
Soulbonder is what a host with soulbonds is referred to.

Fictive was coined by soulbonders some time around 2006 and is a much broader used term for a fictional entity in the system.

Factive is someone in a system who is based on a preexisting person, and some soulbonders may have factives.

Walk-in is a system member who came in from a different place, and can be used to describe many soulbond experiences.