Isaac ( ??? Robin ) is a Venus Adept, a playable character in Golden Sun and Golden Sun: The Lost Age, and a main character in the overall Golden Sun series. He is the silent protagonist and party leader of the original Golden Sun, and gains a speaking role in his appearance late in The Lost Age as a co-leader of the game's extended final party. He returns as an NPC early in Golden Sun: Dark Dawn, where he has become husband to Jenna and father to Matthew. For being the most effective "main representative" of the Golden Sun series, Isaac serves a cameo role in the 2008 Nintendo fighting game, Super Smash Bros. Brawl.
Isaac was born in the secluded town of Vale at the base of the dormant volcano Mt. Aleph, and for his first fourteen years he lived a tranquil life there with his parents Kyle and Dora and his friends Garet, Jenna, and Felix. Like his parents, Isaac is a Venus Adept, and all the townspeople of Vale are Adepts to varying degrees because they live their lives under the influence of a giant Psynergy Stone formation near the town's entrance. Isaac was very reliable and was well-liked by the populace; as an individual, he is virtuous and caring yet not to a fault, and Dora describes him as being so much like his father at his age, including his stubbornness. Isaac used to visit the cottage of the scholar Kraden a lot as well before the elderly alchemist was kidnapped during Saturos' second raid on Sol Sanctum.
Having lived at Vale his entire life, at a mountainous area not close enough to the Great Western Sea, Isaac had never seen an ocean before prior to his quest in Golden Sun, like his friends at that point.
In the Golden Sun series, Isaac is seen as the hero of the story even if he did not know Felix's true objective. He believes everything he does is right if there is a reason behind it. When finding out the true reason why Alchemy must return to the world, he defies The Wise One to join Felix's quest in saving the world from extinction (and saving his father and Jenna along the way).
Isaac, like all playable Venus Adepts, is relatively calm. In Dark Dawn, he does not see his son, Tyrell, or Karis off when they start their adventure. It could be because Dora did the same thing when he started his adventure. A woman in Patcher's Place describes Isaac as a popular person among the ladies.
Open the spoiler to view a comic strip.
Read the comic strip like a manga because it's translated.