Note: Fictional details from the Myst franchise follow, and will be treated as facts.

Screenshot of Aitrus' photo from Riven game

Aitrus (D'ni: Aytrus/[Étrus]) is the paternal grandfather of Atrus (Myst), and father of Gehn (Myst).

Aitrus, born in a minor D'ni noble family, was a member of the D'ni Guild of Surveyors. During a mission to create a tunnel to the Surface, he once again came into contact with Veovis, an old childhood acquaintance. Aitrus and Veovis became friends, a friendship which survived the mission, and which was strengthened when Aitrus saved Veovis' life.

Both Aitrus and Veovis were selected as councilmen of D'ni, and while they often had opposing views their friendship often guided them into finding a solution which had enough consensus.

Their friendship was strained when the human girl Anna came into D'ni. Aitrus quickly recognized her intellect, and after Anna had been allowed to live with his family he began to fall in love with her. Veovis on the other hand hated Anna and all she stood for. While he kept his hostility at bay initially, when he learned Aitrus and Anna (renamed in D'ni Ti'ana) were to be married, he used an old D'ni law to pronounce a veto on it. Calling on the old promise Veovis had made to grant any favour to Aitrus following his rescue, Aitrus managed to get Veovis to retract his veto, but the friendship had ended.

Aitrus and Ti'ana were wed despite moral opposition from the D'ni faction led by Veovis, and a son Gehn was born (named for Aitrus' paternal grandfather). Aitrus also taught Ti'ana to Write, and together they Wrote the Age of Gemedet, thus disproving an old belief only the D'ni could Write.

Although Aitrus had voluntarily resigned from the council following the conflict with Veovis, he remained a leader figure in the D'ni society. Unwittingly he became involved in A'gaeris' ploy for revenge, and Aitrus' testimony against his old friend Veovis caused Veovis to be imprisoned for murder — a crime he was innocent of, framed by A'gaeris.

Veovis escaped, and together with A'gaeris began a terrorist campaign against D'ni, eventually leading to the mass genocide that nearly wiped out the D'ni people and led to the downfall of the empire. During the final struggle with Veovis and A'gaeris, Aitrus lured A'gaeris into the Linking Book for Ederat by Linking there himself, an Age Aitrus had rewritten to be a true inferno, and there both died.

Notes

• Both Atrus and Aitrus would have spelled their names the same in D'ni (ay|t|r|u|s), but the English transliterations have been slightly altered to differentiate between the two. The D'ni vowel in front of their names produces the "Ai" (long A) sound.

• The photograph of Aitrus taken from Gehn's office on Gehn's Age 233 is in fact a photograph of a Confederate soldier from the American Civil War named Benjamin Huger.