Kant Kestner is introduced as a child prodigy who achieved the status of a scientist at the remarkably young age of twelve. His background is marked by the isolation that often accompanies exceptional intellect, as he had a difficult childhood and grew up without friends due to his youth and genius-level mind. This lonely early life significantly shapes his character, making his later connections particularly meaningful.

In terms of personality, Kant is a gifted artist with a deep and specific love for plants, so much so that he bases much of his scientific work and theories on the principles of photosynthesis. This unique blend of artistic sensibility and scientific rigor defines his approach to the world. His primary motivation stems from a profound curiosity about organic energy, though he notably has no desire to travel to Orphan to further his studies, suggesting a preference for his own methods and path of inquiry.

Kant's role in the story becomes clear when he befriends one of the Brain Powerds belonging to a character named Nakki, eventually becoming its pilot later in the series. This transition from an outside observer and scientist to an active participant is a key development. His key relationship is with this specific Brain Powerd unit, as his connection to it allows him to become its pilot. The development he undergoes is closely tied to this bond, moving from a solitary genius to someone who directly engages with the very organic energy he studies by piloting a Brain Powerd. His notable abilities include his scientific genius, his talent as an artist, and his unique capacity to befriend and pilot a Brain Powerd, a feat that is not possible for everyone.