Good Riddles

Question: I am important at the most dangerous times. I can not be seen, heard, or smelled. If you use me too much you would fatally die. What am I?

Question: There once was a king with 3 glasses off water. 2 were completely full and one was half full. What is the king's name?

Question: Wind and cord combine, buzzing in the box. In all this we find, though to some the use is lost. What am I?

Question: I was always in the beginning of time but faded as time passed by. When people use me in a sentence they never forget to use good grammar. When people play dice with me they never win against me but I hate gambling. When people find me they always get a heart of a lion. Who am I?

Question: You are going to make a word. To make this word, you need to put a letter in between two e's to make a word that starts with e and ends with e. What is the word? Hint: Think outside the box.