It has come down to this on Fringe: William Bell is back, and he may have lost every one of his marbles.
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Olivia is seen here on the season four finale of Fringe. Will she make the ultimate sacrifice?
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Fringe Season 4 Episode 22 Quotes

At least now we know how you got shot. I've seen you shot before, like this. You came to me, at the opera house. You said in every version of the future, I would have to die.

Olivia

The bible tells us God created his universe in seven days. It has taken me considerably longer.

William Bell