Grandfather and Grandmother Elf meet each other and fall in love. In order to care for their master after they were two old to care they had one child.
This child would carry on after both Grandfather and Grandmother Elf were too old to serve their master and had their heads chopped off and displayed on the wall. Parent Elf wanted the same fate as their parents - for their head to be chopped off once they were too old to serve their master. They knew they would of served their master and done their job.
Whenever the elf had bad thoughts about leaving master they would punish themselves. Sometimes the punishments were so harsh that they ended up unconscious. This was not good as thy were unable to serve their master when in this state - causing them to punish themselves even more once they woke.