House Umber and House Karstark (or: why everyone at Winterfell was screaming)
Remember these two lesser houses of the North from earlier in the series? Both Stark Bannermen houses rallied behind Robb Stark in the War of the Five Kings, but in season three when Robb was making poor life decisions, he beheaded Lord Rickard Karstark after he murdered two Lannister children in the dungeons of Riverrun. Greatjon Umber dies at the Red Wedding, leaving Smalljon Umber in charge of the house when Rickon, Shaggy Dog, and Osha flee to Last Hearth (and House Umber) in Season 3. This all comes to bite the Starks in the direwolf butt when, in Season 6, House Karstark pledges loyalty to the Boltons and Smalljon Umber makes a deal with Ramsay that leads to the death of Rickon, Shaggy Dog, and Osha. On the bright side, we saw Tormund end the life of Smalljon Umber in the Battle of the Bastards, and this week we learn that Herald Karstark also died at the Battle of the Bastards, off-screen.
These two Houses of the North are at the basis for the first spat between Sansa Stark and newly anointed King of the North, Jon Snow. Jon knows the two castles of the family, Last Hearth (Umber) and Karhold (Karstark) are the furthest North and will be important if The Wall is breached. Sansa thinks that since the majority of House Karstark and Umber have been wiped out and because their previous heads of house betrayed the Stark name and sided with Ramsay Bolton (no mention of poor Rickon, who could not run serpentine) that new Houses should take over the castles. Right in front of all the North, Jon takes a stand saying that he will not punish the sons and daughters of old houses for the actions of their fathers.
At the end of the deliberation scene, we're introduced to young Ned Umber and young red-headed Alys Karstark who both take the knee and re-pledge fealty to House Stark, maintaining their claims over the houses and lands of Last Hearth and Karhold.