Ganishka was a Kushan emperor and one of the most powerful known apostles. He desired first and foremost to extend the territory under his control to every corner of the world. Unlike most apostles, Ganishka opposed the God Hand – Griffith in particular – and aimed to transcend them.
Surviving the ploys of the ever-scheming Kushan royalty and aristocracy throughout his youth hardened Ganishka into a callous, calculated prince, one who brought about the deaths of his younger brother, mother, and father. In order to survive and thrive as a young monarch, Ganishka devoted himself to the art of war, and became convinced that inspiring fear was the only way to progress, all while harboring many unshakable fears of his own. He became increasingly obsessed with reigning supreme over the entire world, all in a vain attempt to quell his own fears.
When he met Guts, Ganishka was impressed by the swordsman's skill, grit, and ability to survive as one who is branded. He found Guts agreeable, and deemed the swordsman's inner malevolence and madness appropriate for the bloodstained world of man.
Unique among apostles, Ganishka refused to submit to the God Hand, believing himself to be the sole individual worthy of reigning over the world. As such, he fostered strong enmity toward Griffith when the White Falcon began thwarting his invasion of Midland. During the Kushan attack on Vritannis, when he finally met Griffith face-to-face, he was disabled by the White Falcon and forced into retreat; thereafter, he acknowledged the immense difference in his and Griffith's power and was left disturbed, exhausted, and humiliated. His resulting humiliation was so great that the emperor lowered himself into the Man-Man Beherit to reincarnate again, in an attempt to surpass the God Hand.
In his twice reincarnated form, Ganishka lost his capacity for rational thought and sense of self, perceiving everyone around him as insects. Initially, he was able to recognize Daiba, but he gradually became disoriented and lost himself in his own immense power. When crushing his army under his footsteps, he expressed glee and likened the resulting gore to blooming red flowers. In the deep recesses of his turbulent mind, however, Ganishka reflected on his lifelong darkened reality and expressed melancholy upon acknowledging the seeming lightlessness of life.