I believe Greatjon died in the Red Wedding, or did I mistake that part?Wild speculation here:
In the books we know that Manderly is a Stark loyalist, and asks Davos to retrieve Rickon from Skavos. Manderly has been casted for the show.
- In the trailer we can see a feast in the Frey common room, with Lannisters. That might be the feast where Manderly serves Frey his own sons to eat (he killed them and put them in a pie).
- The Umbers are also Stark loyalists, but Greatjon being held by the Frey's forces their hand in helping the Bolton's.
Now in the show Smalljon refuses to bend the knee, refuses to make an oath. Yet still brings Rickon and Osha to Ramsay.
- The direwolf head seems way too small to be Shaggydog. Remember how huge Grey Wind's head was on Robb's body.
- Osha tries to kill Ramsay the second she gets free time with him. Now this is not Winterfell held by Theon (20men), the place is swarming with Bolton's, once Ramsay killed she would have not been able to do much, even less free Rickon from the dungeon.
- It may have been the Umber's plan, an inside job. Get Osha to kill Ramsay, help them out once the deed is done. Like attacking Winterfell when their leader is dead, and the house is falling because there isn't any heirs left.
- That plan having failed they turn to option B.
- In the trailer we can see a wildling/Bolton battle. Not hard to guess that it will be the BastardBowl. So in some pics you can see the Umber flag floating behind the Bolton flag. Suggesting they are fighting together.
But it might be part of the Umber plan, and backstab the Bolton army mid battle. Assuring their defeat, stuck between the Wildlings/Eyrie and the Umbers.
- On his side Manderly might work his way into freeing Greatjon from the Freys. But Walder is a coward anyway so if Ramsay get's crushed I don't see him trying to fight his way through the Starks without any assurances (No Tywin, No Rosse).