Answer:
What is the end of everything?
When a doctor hits you with a hammer he is testing this
I am a king but also a common device of measure. What am I?
The eight of us go forth not back to protect our king from a foes attack.
What must be looked through in order to see?
I am the fountain from which no one can drink. For many I am considered a necessary link. Like gold to all I am sought for, but my continued death brings wealth for all to want more.