|Book(s)||The World of Ice & Fire (mentioned)|
Shiera was the eldest child of Lord Roderick Blackwood, who was allied with the Storm King Arlan III Durrandon. Arlan had married one of Roderick's daughters, while Shiera was herself married to Arlan's son. Arlan intended to restore the riverlands to House Blackwood, but Roderick was slain in battle.
After the Battle of Six Kings, Roderick's heir was a boy of only eight and Arlan distrusted Roderick's brothers. Arlan considered granting the riverlands to his good-daughter Shiera and having his own son rule by her side, but the other river lords opposed being ruled by a woman. Arlan instead added the riverlands to the domains of House Durrandon.