Hannibal Barca in the anime Drifters is depicted as an elderly man, having been taken from the end of his life as a historical Carthaginian general rather than his prime. His physical appearance reflects this advanced age, characterized by a long white beard and flowing white hair. He also wears a simple cloth eyepatch over his left eye, giving him the look of a weathered, veteran commander. Despite the frailties of his age, his presence commands attention and respect.

At first glance, Hannibal appears to be suffering from the significant drawbacks of his old age, including senility, dementia, and even incontinence. He often seems confused or lost in his own world, and he has a notable fondness for eating raspberries, which leads the elves caring for him to nickname him the Raspberry Old Man. However, this senile exterior masks a mind that is still one of the most brilliant tactical geniuses in history. He possesses a very calm personality and, in moments of crisis, his eyes clear and his strategic brilliance shines through, revealing a highly intelligent and composed strategist.

Hannibal's role within the group of Drifters is primarily that of an invaluable military advisor, most often to the warlord Oda Nobunaga. Because his dementia renders his speech and behavior seemingly nonsensical most of the time, he communicates his strategies through indirect means. He conveys his insights through seemingly random body motions or simple actions, such as scattering and crushing raspberries on the floor, which Oda Nobunaga is quick to interpret as profound and winning strategies. For example, his gesture of gathering and crushing scattered raspberries was interpreted as a plan to lure the scattered enemy forces into a single point to destroy them. He also demonstrates an incredible ability to instantly assess the unique abilities of his allies and formulate a plan on the spot, such as suggesting a way to create stairs to infiltrate a fortress by combining a skilled archer with a magical amulet. When his dementia recedes and he is fully conscious, his authority as a master strategist is absolute.

One of the most significant relationships for Hannibal is with his historical nemesis, Scipio Africanus, the Roman general who defeated him. In the new world of Drifters, the two former enemies are initially seen arguing fiercely, with Hannibal accusing Scipio of plagiarizing his famous tactics from the Battle of Cannae at the Battle of Zama. Despite their intense rivalry, they hold each other in incredibly high respect and are perfectly capable of setting aside their past to work together as allies to win battles. Interestingly, Hannibal's state of mind is closely tied to Scipio's presence. When separated from Scipio, Hannibal becomes more profoundly depressed and senile, indicating a deep, if unusual, reliance on the man who was once his greatest foe.

Hannibal's development throughout the story is not so much a personal change but a revelation of his true nature beneath his debilitated state. While he remains an aged man dealing with the weaknesses of his body and mind, the narrative consistently shows that his military acumen has not dulled with time. The other characters, particularly the young warrior Shimazu Toyohisa, recognize the fierce, calculating look in his eye that marks him as a true master of war, comparing it to that of a legendary general. His primary motivation is simply the continuation of his identity as a general; even in a strange new world, he insists that victory is always possible and offers his genius to ensure it. His most notable ability is, therefore, his unparalleled tactical mind, which allows him to see through complex battle situations and provide decisive, battle-winning advice even from a state of apparent dementia.