Alba is the central protagonist of the story, a character who has been reincarnated as the son of an impoverished noble family. He retains the full memories of his past life, which shapes his entire worldview and drives his actions. In this previous existence, Alba was an avid player of an otome game, and his favorite character was a figure named Orsis. Upon being reincarnated, his mother remarries into a powerful ducal household, and Alba discovers that his new stepbrother is none other than Orsis himself, his beloved character made real.

Alba's personality is defined by his deep, earnest, and almost reverent devotion to his stepbrother. He is overjoyed at the prospect of being family with his favorite character, but this joy is immediately tempered by a grim recollection from his past life's knowledge of the game's plot. Alba remembers that in the original story, his own character’s death is the direct cause of a tragedy that makes Orsis lose his smile and fall into a dark fate. This knowledge transforms his simple adoration into a powerful and desperate motivation: he is determined to change the course of the story to protect Orsis. His primary goal is not just to live a long life for its own sake, but to live long enough to prevent the suffering he knows awaits his stepbrother, allowing Alba to continue doting on him.

In the story, Alba serves as the proactive force who seeks to alter the predetermined tragic narrative. He uses his memories of the game as a guide, aware of the key events and relationships that lead to the bad ending. His role involves navigating the politics of his new noble family, including his relationship with his new stepfather, Hals, and working to prevent the emotional distance that originally grew between Hals and Orsis. A central challenge to Alba’s plan is his own health. He suffers from a magical condition known as Laonen's Dysmagia Syndrome, which prevents him from controlling his own magical power and causes him to have debilitating seizures. This condition is a direct threat to his survival and thus the central obstacle he must overcome to achieve his goal of a long life. A significant portion of his journey involves seeking a cure for this syndrome, which leads him to venture into dangerous locations like the Agate Forest in search of rare medicinal herbs.

Alba's key relationships are centered on his new family. His most important bond is with his stepbrother, Orsis, the object of his unwavering affection and protection. He also forms a relationship with his new stepfather, Hals, the Duke, and actively works to improve the bond between Hals and Orsis. Through his sincere actions and words, Alba begins to influence the family dynamics for the better, causing Hals to re-evaluate his relationship with his son. His extended family, such as Orsis’s grandparents, are initially a source of conflict, as they do not think highly of Alba due to his background.

Throughout the narrative, Alba shows development as he moves from a state of joyful discovery to a determined resolve to take action. After suffering a seizure and regaining consciousness, he solidifies his goal to live on and witness his brother's future, becoming more proactive in his quest for a cure and in manipulating events to avoid tragedy. He is resourceful, relying on his past-life memories to identify the necessary herbs and plan his actions, even attempting to undertake a dangerous teleportation alone to save himself. Alba's notable ability is not a combat skill but his unique knowledge of the future. He uses his meta-awareness of the game’s plot to identify threats and opportunities, such as recognizing new characters like Bruno, a love interest from the game, and understanding the significance of mysterious plants that can store magical power. His most defining trait is his unshakeable will to use this knowledge to rewrite fate and secure a happy future with his favorite stepbrother.