Who is Fyunch (clicki) from The Mote in God's Eye and what is their importance?

A Fyunch (click) is a role fulfilled by a class or group of aliens. The aliens who fulfill this role come from the Mediator class. The class has been specifically bred and evolved to fulfill the role of consummate communicator. As part of this evolution, Fyunch (click) are all sterile—they are mules and cannot procreate. The class evolved to solve violent conflicts. They do this by identifying so completely with another individual, usually the enemy leader, that they can make up solutions that are acceptable to an aggressor while still having the power to stop the violence.