The Hermit is a Time Lord from New Gallifrey. He chose his name because he has a habit of visiting planets in different times and staying there for a while just to observe closely and then move on to another one. The reason he does so is merely because he finds observing from Gallifrey to be distant and reserved and by studying while on the same planet to be far more useful.
When on Earth in the year 2011, his TARDIS landed within an abandoned flat in a London block and pretended to be a tenant there. It was at this time that he saw that the entire flat had almost completely been abandoned save for a woman, her daughter and a scientist. This was also a point in time where Photo People were invading the flats and taking over the residents there.