᯽the daughter of Ayodhya᯽

Aside from Ram and his brothers, King Dasharatha also had a daughter.
Lord Rama did have a sister. Almost everyone knows about Shri Ram's parents and his three brothers, but few know that Ram also had a sister named "Shanta."
Furthermore, she was much older than all four brothers. Kaushalya was her mother.
It is believed that when Angdesha's king Rompad and his queen Varshini arrived in Ayodhya, they had no children.
During the conversation King Dasaratha learned of this and stated that he would give Shanta to them.
Rompad and Varshini were overjoyed when they learned this.
They looked after her with great affection and took on all of her parents responsibilities.

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A/N: I have done my share of research and I am sure that nothing fictional has been mentioned here.
Valmiki Ramayana does not state the exact same thing.
This is mentioned in Vedas.