All his life, Marcus has been trained to use the dark side of the Force. It is what gave him direction during his youth, it is what helped him survive in adolescence, it is what has marked him for life. Because of this, Marcus has developed a cold and uncaring demeanor which surfaces when emotions run high. Obstacles exist to be eliminated.

This callous and unsympathetic disposition has made Marcus something of an outcast among his peers.

"Betrayer", "traitor", "enemy", "demon". Marcus has been called many names in his relatively short lifetime. After faking his own death at the hands of a Dominion prisoner, he has realized that his entire life amounted to that single moment. Having to die. Now he seeks to absolve himself of past deeds, to offset his lifetime of wickedness with the slight possibility to do good by helping those around him, instead of manipulating them.

This surely does not come easy, and at times Marcus must fight his darker impulses. This can leave him conflicted and undecided, something which might give him pause when no pause should be held.

Marcus Kiriyu possesses a cold and completely uncaring demeanour. This will manifest itself in the fact that when push comes to shove, Marcus Kiriyu will just as soon leave a struggling ally behind rather than put themselves in danger. While this may ensure his survival, it often leaves him as an outcast amongst his peers.

Marcus Kiriyu has a tendency to be secretive and keeps to himself, relying on deception to conceal his motives and intentions. He is a schemer, and plots and plans against others carefully. When dealing with a confrontation, he will try and bluff his way out of trouble, or overcome obstacles with deliberate, covert actions.

Marcus Kiriyu has been noted, at times, for being less than serious in a fight. He will approach any enemy he might see as beneath him with an air of cocky assurance and casual nonchalance, made more poignant by his annoyance that someone dare stand in his way. This is often accompanied by an eye-roll that says, "Now look, you've gone and made me pull out my lightsaber."

Depending on the opponent, this can have an intimidating effect which may help or hinder Marcus Kiriyu's efforts in defeating his foe.

Through careful study and dedication to isolated martial-combat, Marcus Kiriyu has turned the act of dueling into an art form. A keen eye and attention to detail allows him the ability to learn their opponent's idiosyncrasies while fighting. Marcus Kiriyu then uses his own skills to capitalize on the opponent's weakness. Because of this calculated approach to isolated duels, Marcus Kiriyu has a harder time taking on multiple opponents at once at higher skill levels.