Longest New 52 story arcs

[TOXIC]

How about the Court of Owls?

Or Robin's death since it's still going as a story.

[PyroSikTh]

How about the Court of Owls?

20 issues over Court, Night, and City.

Or Robin's death since it's still going as a story.

Batman and Robin #18-Alpha? Maybe, but that's more a series of arcs than one long arc. Each stage of grief was it's own self-contained story, The Big Burn had little relation to the whole Damian thing, and then Hunt for Robin and Robin Rises are more like one arc that leads into another.