He's ba-a-ack, and he's none too happy -- again. "They're laughing at us!" gripes the Frey overlord, whom I have missed greatly since he slaughtered all of my favorite characters at the Red Wedding. It seems that Brynden Tully, aka the Blackfish, aka the uncle of Catelyn Stark, Lysa Arryn, and Edmure Tully, has re-taken Riverrun, and Walder means to take it back. How? By reminding the Tullys who he's keeping as a hostage. Poor Edmure, which is an anagram of demure!
Walder did let slip a few interesting nuggets of info. The Mallisters and a few other previously North-leaning bannermen are back supporting the Tullys. And the Brotherhood Without Banners is stealing supplies from the Freys -- and probably looking to hang a few of Walder's kin, too. Also, Brynden Tully, if you recall, was essentially the sheriff of the Vale at the outset of the series. With Littlefinger and the Arryn army positioned near Moat Cailin, the Blackfish has a probable ally just to the north of the Twins.