The wolf

The general who was acting

He arrives in Rifthold's Great Hall as the King of Adarlan's celebrated Northern General, and he is insufferable about it. Chaol and Dorian dislike him on sight, which is the intended effect. The arrogance is a costume. He has spent ten years being Adarlan's favourite soldier so that Terrasen has somebody on the inside, and he wears a counterfeit of the king's Wyrdstone ring to pass as one of the controlled — his demi-Fae senses having warned him off the real thing.

The confession he did not have to make

In a royal council where the king is hunting traitors, Aedion confesses to treason himself to take the heat off Chaol and the rebels. It is not a gesture; it is an execution sentence, and he knows it. In the glass castle dungeons he hides an infected wound and hopes the fever takes him before the public execution does — a private, unwitnessed way to deny them the spectacle. The Valg prince wearing Dorian finds him, and sends for healers specifically so that he will live long enough to be killed properly.

The cousin

Chaol tells him Aelin is alive. The news does what nothing in ten years has managed: it gives him something to want. She allies with Arobynn Hamel — her old master, the last man she would choose — to get him out, and frees him on the execution floor. They fight their way through the hall and out across the castle gardens toward the wall, and that is the reunion: two cousins running, armed, in public.

Gavriel

At Skull's Bay, Rowan works out what Gavriel already knows — the Lion of Doranelle is Aedion's father. Neither of them is any good at it. The closest they get is during the siege, when Gavriel asks whether Aedion wants to hold a gate together, and Aedion says yes. Gavriel dies sealing the western gate so that Aedion and everyone behind him survive. Afterwards Rowan tattoos his name onto the Knot of Terrasen over Aedion's heart, with the others. He gets his father's name on his skin and never once got to use the word.

Orynth

With Aelin taken and Lysandra publicly wearing her face, Aedion leads the allied army north and then holds Terrasen's capital against Morath with too few soldiers, no supplies and a wound he is not mentioning. Darrow — who spent two books refusing to crown Aelin, and is moved by Evangeline of all people — hands him back the Sword of Orynth mid-siege. He kisses Lysandra once before the last stand, calls her the woman who should have been his wife, and promises to find her again in whatever comes next. They both live. In the epilogue they marry.