Intermediary

undefined:

An intermediary is a headmate that focuses on external relationships involving their system. The relationships can be of any kind, such as romantic or platonic, the sysmates involved can be any number, and it can be with a singlet partner or a partner system. The only defining trait is that the relationship is out-of-system, occurring in shared reality.

Intermediaries can either mediate the relationships, making them better, or sabotage them, making them worse.

Related Terms
Intermediary somewhat functions as a combination of peacemaker and instigator.

This was directly inspired by the term moderator, which is a mediator for intra-system relationships.