Answer:
A leathery snake, with a stinging bite. I'll stay coiled up, unless I must fight.
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.
What do people want the least on their hands?
The eight of us move forth and back. To protect our king from the foes attack.
What can be filled with empty hands?
This food is a tortilla filled with cheese and sometimes chicken before being heated or cooked.