Kay
Kay was Arthur's foster brother, whose father was also Ector. He was older than Arthur, and even though he was older, he was sort of pushed aside once Arthur pulled the sword Excaliber out of the stone.
Kay was a knight at Arthur's Round Table, so he wasn't completely forgotten by Arthur. However, Kay played a very important part in Arthur's tales. If Kay wouldn't have asked Arthur to go find him another sword, Arthur would have never attempted to pull the sword out of the stone, thus never becoming king. Kay's part in the tales of King Arthur was helping Arthur to run the castle as his seneschal. He also helped Arthur discover that he was truly meant to be a king.
Kay was a knight at Arthur's Round Table, so he wasn't completely forgotten by Arthur. However, Kay played a very important part in Arthur's tales. If Kay wouldn't have asked Arthur to go find him another sword, Arthur would have never attempted to pull the sword out of the stone, thus never becoming king. Kay's part in the tales of King Arthur was helping Arthur to run the castle as his seneschal. He also helped Arthur discover that he was truly meant to be a king.