Originally a terrorist in a war-torn region, Krake was killing people as early as his teenage years, including his own parents and slaves he owned who he considered incompetent workers. Upon joining Cobra, he further displayed his ruthlessness on a number of occasions, such as when he tried to wipe out a whole village's population. After the previous Cobra Commander's death, the ruling council organized a competition; whichever top agent of Cobra killed the most Joes would "win" and become the new Cobra Commander. Krake, by combining his kill-count with that of other Cobra agents, cheated his way to the title...and then promptly slaughtered the ruling council so that his leadership and authority within Cobra would go unopposed.
Now in control of all of Cobra, Krake led an onslaught on the entire country of Nanzhao, an act that saw hundreds killed before Krake took it a step further by nuking all of Nanzhao's major cities and rendering the whole area irradiated and uninhabitable.
Not about to stop there, Krake also had airports attacked, more cities bombed, and a plane dropped on Paris just to kill one person. Having never abandoned his practice of slave-owning either, Cobra under Krake has slave labor camps around the world, with adults and children alike either working day and night for him, or in some cases being sent to undergo brutal, harsh, remorseless training to become twisted and fanatical Cobra soldiers.
G.I. Joe: Renegades
G.I. Joe: Retaliation