Answer:
As light as a feather, but you canβt hold it for ten minutes.
My first master has four legs, my second master has two. My first I serve in life, my second I serve in death. Tough I am, yet soft beside. Against ladies cheeks I often reside.
To unravel me you need a simple key, no key that was made by locksmith's hand. But a key that only I will understand.
I have rivers without water. Forests without trees. Mountains without rocks. Towns without houses.
What has 13 hearts but none beat?
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.