|doctor (n., adj.)|
A doctor is a headmate whose role is splitting or fusing other headmates. They can also fall into other roles such as persecutor and may be highly dangerous. They can also be a protector and chose to fuse in polymated systems in order to keep the number of members in a system down to a safe minimum.
Some might be able to dissipate, but protectors often dislike using this tactic except as a last resort. They can be thought of as doing minor and major surgeries like a doctor.