Jack Dent? No idea. But I do have a few theories.
I think there might be many Jack Dents. Each one in his own little world being, well Jack Dent.
There are multiple[1] Jack Dents[2] in this world.
Taken from User:Lord Matt/UserBoxes.
The chances are that you have no idea what this "Jack Dent" business is about. Feel free to revel in your lack of understanding with me.
Really? Well, okay then. If you really think you know more than those that don't here are the userboxes that you might need. Good luck with that. Perhaps someone might like to add, you know, actual graphics to these user boxes.