Ranmaru Riddle

Here's a riddle for you all. Try your best to figure it out.

I can be found where anything cannot; dead men eat me all the time, but if a living man eats me, he'll die.
What am I?

can you give us a clue?

I can't think of anything without making it too obvious so just do your best. Read the riddle carefully & comprehend the words.

okay hmm..... this is tough

Read this very carefully. I can be found where anything CANNOT;

The answer is nothing... literally 'Nothing'. If we eat nothing we die. Dead men eat nothing all the time. If something isn't somewhere there is nothing.