- Catelyn Stark: "And Arya will marry his son Waldron when they both come of age."
- Robb Stark: "She won't be happy about that."
- — Catelyn relaying the terms of Walder Frey's alliance.[src]
When Catelyn Stark negotiates with Walder Frey to gain permission for her son Robb Stark and his army to pass The Twins, Walder demands that Arya Stark will marry his son Waldron. Catelyn and Robb accept his terms.
In the books
In the A Song of Ice and Fire novels, Arya is betrothed to Elmar Frey. The character has been renamed for the television series. Elmar is the twenty-second son of Lord Walder Frey and the fourth born to Lord Walder's seventh wife, Annara Farring. Elmar is the older brother of Shirei Frey, the youngest child that Lord Walder had with Annara Farring.
- Elmar Frey at a Wiki of Ice and Fire (spoilers from the books)
|Lord:||Lord Walder Frey||Heir:||Ser Stevron Frey|
|Seat:||The Twins · Riverrun||Lands:||Riverlands|
|Title(s):||Lord of the Crossing · Lord of Riverrun|
|Current members:||Arwaya Frey · Derwa Frey · Freya Frey · Janeya Frey · Lothar Frey · Marianne Frey · Merry Frey · Neyela Frey · Olyvar Frey · Roslin Frey · Sarra Frey · Serra Frey · Shirei Frey · Walda Frey · "Fat Walda" Frey · Waldra Frey · Waldron Frey · Ryger Rivers · Black Walder Rivers|
|Deceased members:||Joyeuse Erenford|
|Household:||Malcolm · Talbot|