the narrator talks about the ring as if it were as character with its own personality and motivation. What sort of character does the ring seem to be?

THis is a neat question! The ring is an extension of all things evil. It attracts all the primal urges people and other creatures harbour and bury deep within their soul. So the ring becomes a personification of greed, envy, obsession, power...It takes on these very characteristics in whoever the bearer is. Nobody, not even Gandalf, is immune. Consider what happened to Gollum. The ring can be a metaphor for so many things in our world today if you think about it.