The title of this article is conjecture based on information revealed in the A Song of Ice and Fire novels and may be subject to change.
Date of birth
Arys Oakheart is a recurring background character in the first and second seasons. He is played by an unidentified extra and debuts in " You Win or You Die". Ser Arys is a knight and a member of the Kingsguard and defends King Joffrey Baratheon as he defended King Robert Baratheon before him. He is sent with Princess Myrcella Baratheon to Dorne.
Ser Arys was among the guards that attacked
Eddard Stark when he tried to de-throne King Joffrey. He was also present when Ser Barristan Selmy was dismissed of the brotherhood 
Ser Arys in Princess Myrcella's retinue
Ser Arys accompanies Princess
Myrcella Baratheon as her sworn shield for her journey to Dorne.
Season one appearances
Winter is Coming
Cripples, Bastards and Broken Things
The Wolf and the Lion
A Golden Crown
You Win or You Die
The Pointy End Baelor
Fire and Blood
Season two appearances
The North Remembers
The Night Lands
What is Dead May Never Die
Garden of Bones
The Ghost of Harrenhal
The Old Gods and the New A Man Without Honor
The Prince of Winterfell
In the books Edit
novels, Arys Oakheart is a member of Robert Baratheon's Kingsguard. He's a member of House Oakheart, a noble house from the Reach.
A Song of Ice and Fire
He is regarded as one of the kinder Knights of the Kingsguard under King Joffrey, objecting at first to
Joffrey's orders to beat Sansa Stark, then only hitting her as lightly as he dares. He is also of a much more pleasant demeanor, often engaging in pleasant conversation with the Stark girl.