|Father:||James T. Kirk|
Occurs in an alternate mirror universe:
After Commander-in-Chief Spock was overthrown by the Imperial Starfleet, Marcus led a resistance movement dedicated to carrying on Spock's vision of reform, but his activities unfortunately helped fuel the rise of the Klingon-Cardassian Alliance and its subsequent conquest of Earth. Beset by guilt over his role in this, Marcus took his own life.
Decades later the Klingon Kruge, who worked with Marcus in the resistance, joined the Terran rebellion in Marcus' name. Kruge hoped by doing so he would grant Marcus a place in Sto-vo-kor. (A Debt of Honor)
In another timeline Marcus was killed trying to free scientists from a prison planet.