In the books
Lord Sawane has six sons. The eldest, Harren, was killed at Moat Cailin by a poisoned arrow fired by the Crannogmen. This left his second eldest, Tristifer, as his heir. Tristifer is one of the close champions and bodyguards of Asha Greyjoy (renamed Yara in the TV series). They sexually experimented with each other when they were teenagers. He proposes to her, but she isn't romantically attracted to him anymore, thus his love remains unrequited. She thinks of Tristifer as a lovesick puppy but he is quite loyal to her.
Prior to the Kingsmoot, Lord Sawane states that the Seastone Chair belongs to Theon Greyjoy by right, as Balon's only surviving son. In response, Euron has him drowned and dispossessed his sons of the lordship. Half of the lands are given to House Wynch, while the remnants are left to Sawane's brother Germund, the new Lord of Lordsport. Tristifer, the legal heir of his house, hopes that if Asha is elected as queen she can restore rule of House Botley to him as is his right.
After Euron wins the Kingsmoot, Tristifer flees the Iron Islands with Asha back to her garrison at Deepwood Motte. Tristifer tells Asha about Torgon and the cancelled kingsmoot, and that gives Asha an idea. Just then, Asha's garrison is attacked by Stannis Baratheon's army and some of the northern mountain clans, killing almost all of the two hundred ironborn at the castle and destroying her ships. Along with Asha, however, Tristifer is one of the less than ten ironborn who are captured alive.
Houses from the Iron Islands