Answer:
Take one royal word in the plural and make it singular by adding one letter
What can be seen but not touched?
Made of ten but two we make, When assembled others quake, Five apart and we are weak, Five together havoc wreak. What are we?
Barren location, infertile and dry; my name means "to leave", it's not heard to see why
What is the word that even in plain sight remains hidden?
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.