Nowell (ノーブル, or Noble in the original Japanese) is a character in Golden Sun: Dark Dawn. All that is known is she is the 16 year old daughter of Mia and the sister of Rief. The name "Noble" appears to fit the theme implied by Rief's Japanese name, Crown. As a descendent of the Mercury Clan, it is implied that she is a Mercury Adept.
Along with her brother, Nowell is one of Kraden's apprentices pursuing the knowledge of alchemy, particularly the appearance of dark psynergy. She initially appears with Kraden and Rief while investigating a psynergy vortex, when Matthew and his party meet them in a mine. When Rief is kidnapped by Blados and Chalis, Nowell and Kraden head for the north entrance of the mine while Matthew, Tyrell, and Karis go to the south entrance in hopes that one of the groups will be able to save Rief.
While Rief is eventually rescued by Matthew and his friends, Nowell and Kraden do not join up with them in the aftermath. When Kraden appears again and joins the party as an NPC, he reveals that he and Nowell had met up with Captain Piers and had been traveling with him. However, Nowell does not reunite with the party of adepts and decides to remain with Piers, having, as Kraden suggests, fallen in love with Piers. Afterwards, Rief says to Kraden that Nowell was always the lucky one, to which Kraden replies that he wouldn't say that if he knew where they were sailing to.
Since she has a face graphic, even though she just briefly appeared in the game, it's theorized that she could be playable in a possible, fourth Golden Sun game. Yet this simply could be due to the fact that Nowell is the daughter of Mia, and sister of Rief.