Lifeline
This term is a holder subtype.
A Lifeline is a headmate that holds suicidal thoughts, memories, or acts. This headmate may be either more suicidal than the rest of the system, or significantly less due to desensitization, absorbing the thoughts and feelings from other headmates.
These headmates typically absorb these feelings to help process them, however they may also monitor other suicidal headmates. They may try to stop the planning, consideration, or attempt at suicide. This, however, doesn't mean the headmate won't also plan, consider, or attempt suicide.
A subtype of this role would be a Self-Inflictor, which is a headmate who indulges in the act of self harming. This could any form of self harm.