Season 6 is presumed that Eddard to returned the blade to House Dayne. I believe Howland have kept the Sward of Morning. Jojen and Meera Reed have never talked about Howland the Robert’s Rebellion or the Tower of Joy event. I think Eddard had asked Howland to deliver the Sword of the Morning to the House Dayne, but he couldn’t do it because he oathbreaker to stab Dayne. Over the years in support Eddard, he wanted to get back his promise, especially with the Stark House/War of the Five Kings and Ban cribbed, to get a Quest to visit the Three-eyed Raven.
Does anyone different thoughts?