This episode pissed me off. How can they still be adding questions to the story. Where did the mother come from? What the hell is the light? Is MiB dead or is he smokey? Did the writers REALLY have the skeletons planned?
AND THE BIGGEST QUESTION OF ALL...
How did the mother fill in a mine, kill 20 armed people and burn down their village all by herself?!?!
I don't need to know where she came from - her line has always been and always will be. Like the knights guarding the Holy Grail, she is there to protect the light.
The light is all things beautiful - love, honesty, beauty, perfection - what you see is different for every person, but it's always beautiful. It is the thing that holds all the worlds together, the centerpiece of existence. Like gravity, it's real but we don't fully understand how it works, although magnetism is definitely a part of it. Like the not mom said - there's a little piece of it in every man, but they always want more. Perhaps that little piece is our soul, and the voices are the souls returned - it's why Smokey could see dead people before, and why he can alter himself into them after.
Jacob's brother is Smokey. So is the light, now. Or at least the beast is some sort of combination of the two.
And the last question is easiest of all - with the help of the island. Yea, I don't exactly know what that means either, but it's the same way she made the boat crash (A storm? Yea, we've heard that before), and as guardian it's clear she can command the power of the island in some ways, whatever that might mean. Smokey might be the spliced version of that power, but it was there before he was created. If she (and others like Jacob) can change the weather around the island (or the island does it) to bring in the candidates, certainly it can collapse the mine.
As to the people - she poisoned them.
Hey, when a tool works, you use it more than once.
At least, that's what I got out of the episode.