The Master

Colonel Alexander "Flynn" Marco, commonly known as "The Master" is the elusive, secretive and well-informed leader of Chronos. His appearance is unknown to the public as he has only revealed himself through distorted holograms and computer-hacks. The Master was responsible for the rebuilding of Chronos and the infamous Massacre at Thaden. He is a colonel from the Alliance Navy gone rogue after faking his own death.

Background
Born on Earth on the 18th of March, 2154, little is known about Marco's early life. He enlisted in the Alliance Navy when he was eighteen years old and joined the Systems Alliance N7 special forces program and successfully graduated as the top of his class. While on the program, he met Shepard and the two became close friends. While Shepard grew to the ranks and eventually reached the title of Commander, Marco instead chose to become an intelligence officer and reached the rank of Colonel.

While working as an intelligence officer, he and Shepard worked together on various missions. While Shepard was doing the groundwork, Marco stayed behind in a ship to brief Shepard and guide him in his missions. The last mission Shepard and Marco worked on went horribly wrong. Apparently, Shepard and Marco were tasked to terminate an illegal weapons trafficking facility set up by vorcha pirates on Adas in the Terminus Systems. The vorcha had gotten wind of the Alliance's presence on the planet and fired a missile straight onto Marco's ship, forcing it to crash. Afterwards, Shepard fought off the vorcha while trying to contact command to get an evacuation. Shepard insisted on going back for Flynn, but instead they left the planet, believing him to be dead.

Years later, Marco resurfaced once again under the alias "The Master", the enigmatic leader of a resurgent Chronos. He has since rebuilt the organization and began to expand its territories across the Terminus Systems, all the while trying to lure Shepard to him for the ultimate endgame.

Mass Effect 2
The Illusive Man sends Shepard on a scouting mission on Thaden. Shepard there finds a destroyed colony and murdered Asari. The Master then reveals himself through a distorted hologram, claiming that his actions on Thaden were the cause of a greater good. Depending on which dialogue option the player chooses, Shepard may tell the Master to turn himself in peacefully, or they may threaten him.

Quotes

 * "You came all this way for answers. Only currency I have."
 * "Earth sleeps ahead of you, its nightmares filled with quakes, storms. You'll need to find your own path."
 * "Who are you, that do not know what your history?"
 * "To the Threshold they came... in the Threshold, they rest."
 * "Burn away the flags. Begin again."
 * "No need for bombs, when hate will do."
 * "The Olympus Threshold... this place is a slice of it. Old military. Can still smell the pride. And the fear. Hope of the old world, wrapped in fencing, covered in storm."
 * "Road gets rougher from here, Commander. Left marks for you - colors'll tell the way - if you're smart. They'll lead you to your home one more time, lead to the ending of it - maybe remind you why you wander."
 * "Home isn't where you're born into this world."
 * "You have forgotten all you were, traded glory for savagery. Fitting."
 * "If war doesn't change, men must change, and so must their symbols. Even if it is nothing at all, know what you follow, Commander..."
 * "If you feel its loss... remember you could have turned away at any time. Gone back home, and none of this would have happened. But you had to make one last delivery, and that's why I knew you'd come, Commander. Couldn't stay away, it's who you are."


 * "The day I set my flag down, it'll be over my body or over a nation I believe in."


 * "Before you... this is the edge of the Threshold. Ahead lies your work, the history you burned in the earth. What you brought to the people here."
 * "You gave it a name. What was it to you? Companion? Slave... weapon? All of that, nothing compared to its primary function. It's a messenger. Like us... and it shares our history."