Aron Lannister

Lord Aron Lannister, born Eddard Stark II, is the first twin-son of Ned and Catelyn, and their heir to Winterfell and the rightful King of the North. From birth, Eddard was warded to Tywin Lannister as a peace treaty between their families, however, Tywin grew attached to him and renamed him Aron Lannister, his third son, and legitimized him as his third heir to Casterly Rock.

Aron is gifted with the old arts and from the age of fourteen, he served on King Robert Baratheon's small council as the Master of the Old Arts. He continued to serve when his nephew's Joffery and Tommen ascended to the throne. Following Tommen's suicide, he was set to ascend to the Iron Throne thought his father's claim but Cersi outed him as a Stark and he was forced to flee to the North to find his true family.

Early Life
Aron was born, Eddard Stark II, to Eddark and Catelyn Stark in 242 AC. He is the older twin brother of Robert Stark but was warded off to Tywin Lannister when the Starks and Lannisters began feuding. Tywin accepted the Stark's first born and heir, and made peace with the family.

Had Aron not been warded to Tywin, he would have been Ned Stark's heir to Winterfell but instead his younger twin brother, Robb Stark, became the heir. Only Ned, Catelyn, Tywin and Maester Luwin ever knew about Aron being a stark. Aron's older 'siblings' also knew of his true heritage although they never revealed it with both his brothers treating him well.

Throughout his childhood, Aron was a decent soldier due to his training alongside Jaime, however, he was very intelligent and at one point wished to become a maester, though Tywin encouraged him to instead train himself in the Old Arts such as with Alchemy and Mystics, he also had a knack for certain magic through prayer which he came to enjoy. On his 15th Birthday, he moved to King's Landing to serve Robert Baratheon as his Master of the Old Arts, making him the youngest small council member in history.

Season 1
When his true father, Ned Stark, arrived in King's Landing, Aron showed great admiration for the man, not believing his brother's lies about him. He proved a loyal member of the small council to Lord-Hand Stark, providing him with guidance on several occasions.

When King Robert was injured on his hunting trip, Aron grew colder and warned the hand that he should be careful. When he is confronted about his brother and sisters relationship, he denies knowing anything before coming clean, he states that it does disgust him but if he were to tell his father, he would cast them out and he would become the heir to Casterly Rock, which he did not want. When Ned asked for Aron's backing against Cersi, he would not give it, stating that Cersi is his sister and he would not turn against his own family.

Following Ned's arrest, Aron tried to convince Joffery that he should be sent to the wall instead, Joffery tried to threaten Aron but failed and instead found himself at odds with his uncle. Aron later thanked Joffery for changing his mind.

After Joffery sentence Ned to death, Aron attempted to plea with his nephew but failed before spotting Arya Stark in the crowds and managing to lead her away to save her. Although Ned never knew that Aron saved his daughter, Arya never forgot what a Lannister did for her.

Following the execution, Aron remained cold to Joffery and refused to work with him on the small council until Tywin personally requested he move past it. Aron went out of his way to protect Sansa Stark on numerous occasions from Joffery's wrath and even threatened his sister with the truth about Joffery's heritage.