How Gyp Rosetti meets his end in Boardwalk Empire — and who betrays him

Gyp Rosetti (Bobby Cannavale) dies in the Boardwalk Empire season 3 finale, "Margate Sands," first aired December 2, 2012.

The man who kills him is his own lieutenant, Tonino Sanfilippo — a knife in the back on the beach, delivered while Gyp is happily singing to himself. But the betrayal that actually doomed him happened earlier, in a back room, and it wasn't Tonino's.

How Gyp lost the war

For most of season 3, Gyp is winning. The Sicilian gangster chokes off Nucky's liquor routes at Tabor Heights, bombs the Boardwalk — the blast that kills Nucky's mistress, Billie Kent — and finally seizes Atlantic City itself, backed by an army of Joe Masseria's soldiers from New York.

Then Nucky rebuilds.

He allies with Chalky White's men and the Chicago gunmen Al Capone brings east, and together they ambush and slaughter Masseria's departing troops. The decisive blow, though, is a business deal: Arnold Rothstein agrees to make Masseria pull his support — in exchange for Nucky handing over a 99 percent stake in Mickey Doyle's Overholt distillery.

Masseria withdraws. Gyp is suddenly a general without an army.

The knife on the beach

While Richard Harrow storms the Artemis Club alone and wipes out Gyp's remaining crew to rescue Tommy Darmody, Gyp slips away to the shore with Tonino. He's in a good mood — mocking Nucky, singing the novelty song "Barney Google" — when Tonino, who understands exactly how this war has ended and wants to survive it, drives a knife into his back. Tonino is then sent to New York to tell Masseria how it all turned out.

It's a fitting exit for a man who announced his worldview in his very first episode, "Resolution":

"Nothing's personal? What the f*** is life, if it's not personal?"

The moments that made him unforgettable

• The tire iron — in his first scene, he beats a helpful stranger to death over a harmless remark, then takes the man's dog.
• The gas station — he douses the sheriff of Tabor Heights in gasoline and sets him alight for a perceived slight.
• The belt — his private appetites, discovered at Gillian's brothel, hand Nucky's side leverage nobody wanted to know about.
• The sing-along — even his death scene is a joke at his expense; the knife lands mid-verse.

Why he only lasted one season

Gyp was built as a one-season antagonist — a man so thin-skinned that every insult became a war, which made his downfall inevitable from the start. Bobby Cannavale made the most of the runway: the role won him the 2013 Emmy for Outstanding Supporting Actor in a Drama Series.