What Am I Riddles

Question: The person who buys me doesn't need me, the person who makes me doesn't want me, and the person who uses me can't appreciate me.

What am I?

Question: You use a knife to slice my head and weep beside me when I am dead.

What am I?

Question: Alone I am 24th, with a friend I am 20. Another friend and I am unclean.What am I?

Question: I am greater than God, more evil than the devil, the poor have me, the rich don't, and if you eat me, you'll die.What am I?

Question: With pointed fangs I sit and wait, with piercing force I serve out fate. Grabbing bloodless victims, proclaiming my might; physically joining with a single bite.What am I?