Riddle 5

Question: I am unseen but all people know of me. I am intangible yet sharper than any sword. I come from nothingness but can fell even the mightiest kings.

Question: People see through me, but none pass through without killing me. I can be anywhere, and can be seen double or single. What am I?

Question: During what month do people sleep the least?

Question: When is 99 more than 100?

Question: What can be broken but never forgotten?

Question: What gets broken without being held?