Gus.  In the season 4 finale, Gus said he would kill Walt's whole family if he tipped off the DEA about going after Hank. 

Gus.  In the season 4 finale, Gus said he would kill Walt's whole family if he tipped off the DEA about going after Hank. 

One of the episodes in season five is titled 51, so chances are we're a year+ away from the flash forward.

One of the episodes in season five is titled 51, so chances are we're a year+ away from the flash forward.