Henry is a good candidate for being "HIM", he certainly seems to be in charge of The Others we've seen.
Personally I think Alvar Hanso is a better candidate, but no-one knows yet.
One thing we do know is why there are Polar Bears on the island, DHARMA put them there to study, there was a reference to them on the map...
quote:
STATED GOAL, REPATRIATION ACCELERATED DE-TERRITORIALIZATION OF URSUS MARITIMUS THROUGH GENE THERAPY AND EXTREME CLIMATE CHANGE
But they seem to pop up in other places, the comic book, the You All Every Butties advert, Michael gives one to Walt when he was a baby...
They'll be back in season three I hope, we're supposed to be getting a look at the Zoological Research Facility at some stage, or what's left of it...
Live Together, Die Alone