Piers

Piers is a Mercury Adept from Lemuria. His age is unknown, although he has the appearance of a teenager. All Lemurians have uncannily extended lifespans thanks to a mystical influence that hangs over Lemuria that prevents its inhabitants from aging at the standard rate. It is implied that he could be centuries old. He never reveals his exact age, though, possibly not wishing anyone to treat him like an old person.

Background
Piers lived with his mother and uncle for a long time. Not much else is known.

In Golden Sun: The Lost Age
The lighting of the Venus Lighthouse by Saturos and Menardi causes a tidal wave that drives Piers out of Lemuria on his ship. He heads towards a foreign continent to rest and is suddenly apprehended by soldiers from a town that was recently raided by pirates, and Piers is falsely accused of being in league with them and held in jail. Felix comes along in search of a ship himself and decides to clear Piers' name in hopes that they can use Piers' ship together. Thankful for the help, Piers lets Felix on his ship and lets Felix command their now-sea-faring party as they embark on a large oceanic venture.

After a great period of time exploring the Great Eastern Sea, Felix and Piers make a successful attempt to reenter Lemuria, and Piers is allowed back in with his newfound friends, where he soon finds that his mother has died due to sadness and a weak heart. Piers finds the time to pay his last respects to his mother before going with Felix to his king Hydros (this is notably the only time in the series were a character temporarily leaves the party). Their lengthy discussion with the king reveals to Felix for the first time that Alchemy's absence is what has been causing Weyard's waning over the ages. Hydros therefore tasks Piers to accompany Felix on the rest of Felix's quest to activate the remaining two Lighthouses and save Weyard from eventual collapse.

However, Hydros' lord advisor, Conservato, objects to the belief that Alchemy is not the destructive force he has always believed it to be personally. Therefore, Conservato assures Piers that he will be banished from Lemuria if he leaves to accompany Felix, but Piers accepts this consequence and leaves Lemuria with Felix as they head out on the final stages of Felix's journey. Eventually, after a great deal of drama, Alchemy is restored, the world is re-sustained, and Piers is entirely content with considering all his new friends as his new family.

Fan influence
Fan fiction depicting Piers does not often depict him in a Shipping relationship with other characters. When he is paired, it is fairly usual to see him with Felix, Jenna, or Mia. In the younger days of the fandom, there was a movement to call Piers by his Japanese name. One group of fans called themselves the OBHL, or Obsessors of a Blue-Haired Lemurian, and they coined the phrase "POW POW PICARD!" as a rallying cry. These days, however, the majority of fans have accepted Piers' name.