1. Is it a person? not precisely
2. Is it evil? yes
3. Is it a ork/goblin/Urukhai? no
4. is it a sentient being? uhm... sure.
5. is it a spirit? warmer, warmer....
6. is it the malicious spirit/thing that was in the 3-headed statue guarding the gate to the tower at Cirith Ungol? no
Okay, a hint. It's only in the FotR BOOK.