I don't live but all life has me.
It ain't easy to destroy me, but if you do, I'll destroy you.
You won't see me as me.
My sibling is known as tekahaamandlakusogzogikethamopolmphamvu
And..
My name is a tiny little word
Also..
I am not oxygen
I wasn't able to make a proper rhyme out of these, so any edits for it are always welcome.