Raised in the desert by his grandmother Ti'Ana and brought to D'ni by his father Gehn to be taught the Art and legacy of the fallen D'ni Empire, Atrus is the central figure in the Myst saga as both the bearer of burden and the rebuilder of D'ni civilization.
After rejecting his father's demands to mend his collapsing Fifth Age, he and his newly-wed wife Katran (who he nicknamed Catherine) trapped Gehn on the Fifth Age of Riven before escaping to Myst Island through a mysterious rift in the fabric of space-time known as the Star Fissure which had begun to rupture Riven.
They raised two sons, Sirrus and Achenar, who like their grandfather were seduced by the power of the Art and carried through a plan to trap their parents and plunder and conquer the many Ages of Myst. In their quest for power and greed they would ultimately trap themselves in two separate prison Ages and when all seemed lost, Atrus would be freed by an unknown stranger who had discovered his lost Myst linking book that he had let fall through the Star Fissure.
Following Atrus' freedom from his entrapment in K'veer, he began the task of searching for D'ni survivors throughout the many books in the D'ni Cavern in the hope of restoring that once great civilization.
After amassing a large following of D'ni people in the Ages he had searched he attempted to rebuild the D'ni city. After much thought he decided against it and chose to write a new Age for his people which he named Releeshahn. This new Age married all the great teachings of his grandmother and the ancient concepts regarding the Art into what he deemed "the whole".
Atrus would have a third child named Yeesha who he nicknamed his
'desert bird' who would one day leave the comfort of his home and enter the D'ni caverns in her own quest to understand her path and legacy.
Catherine (or Katran in her native Rivenese) was child prodigy on her home Age of Riven, educated in the Art by Gehn's Rivenese guildsmen and chosen by Gehn to be his wife.
Following Atrus' arrival on the Age, she developed a relationship with Atrus, bonding over shared interests in the Art and hatching a plan to entrap Gehn on Riven in order to prevent him from furthering his misguided conquest of Ages in his belief of rebuilding the lost D'ni Empire.
She would go on to marry Atrus and live out a peaceful life on Myst Island until her sons betrayed her and Atrus, trapping him on K'veer and her back on Riven.
Catherine's talent was her ability to dream Ages - Ages that broke almost every rule of the Art and were often deemed impossible by Atrus.
During her entrapment on Riven she was brought to the rebel Moiety hide-out where she was worshiped by her Rivenese brethren as a deity - a fact which she strongly disliked. Ultimately she would aide the Moiety in writing her people a new Age to escape to named Tay following the destruction of Riven.
After the events of her imprisonment on Riven she would go on to help Atrus in his rebuilding of the D'ni civilization along with raising a new daughter named Yeesha.
Born in D'ni on the eve of its destruction as a half-breed by his mother Ti'Ana who had come from the surface and his father Aitrus, a D'ni man on noble descent, Gehn suffered the worst of fates - being born between two worlds. Mocked by his D'ni peers and burdened with being a worthy successor to his father's legacy, Gehn suffered a difficult childhood.
Following the Fall, he grew to resent his mother for the cause of the destruction of the only civilization he knew. Becoming obsessed with D'ni's grandeur he came to regard it as the apex of civilization and sought at all costs to rebuild it in its magnificence - and ultimately his own image.
Gehn's major flaw was that he was not educated in the Art but chose to write Ages with a plagiaristic approach. Rather than improvise like Atrus he would rigorously copy passages from ancient D'ni descriptive books to use in his own books, ultimately creating links to unstable Ages.
His second and most egregious error was his assumption that he was the God of his Ages, having written everything within them - every plant, rock, animal, or person - out of thin-air, directly in contradiction to the beliefs held by the D'ni up until their demise.
Gehn would be trapped on his Fith Age of Riven (he did not name his Ages but rather numbered them) by his son Atrus and his wife Catherine. He remained there for thirty years, building a mock D'ni Empire on the Age's islands before succeeding to escape to his 233rd Age - his first stable Age where he constructed his office to watch over the inhabitants of Riven.
Gehn's fate is ultimately unknown since on the verge of finishing his 234th Age he was trapped on a prison Age by Atrus' friend, the unknown stranger, as part of Atrus' mission to rescue his wife Catherine.