Shoto Todoroki is the youngest son of pro hero Endeavor (Enji Todoroki) and Rei Todoroki. His birth resulted from a Quirk marriage arranged by Endeavor, who sought a child combining his fire Quirk and Rei's ice Quirk to surpass All Might. Shoto's older siblings—Toya, Fuyumi, and Natsuo—lacked this dual inheritance, leading Endeavor to declare Shoto his "masterpiece." Endeavor subjected Shoto to harsh physical training starting at age five; these sessions often pushed Shoto beyond his limits, causing illness, and Endeavor struck Rei when she intervened. This abuse contributed to Rei's declining mental health. As a child, Shoto observed his siblings playing together but was isolated by Endeavor, who stated they inhabited "different worlds." Toya, resentful of being replaced, once attacked infant Shoto with his fire Quirk, stopped only by Endeavor. Following this, Shoto was separated from his siblings. Rei supported Shoto, urging him to become a hero despite the abuse. She shared All Might's belief that one could forge their own path, telling Shoto he was "not a prisoner of his bloodline." However, Rei suffered a mental breakdown triggered by Shoto's resemblance to Endeavor and poured boiling water on Shoto's left face, leading to her hospitalization. Endeavor coldly informed Shoto of this, cementing Shoto's hatred for his father. He blamed Endeavor for Rei's actions and vowed to reject his fire Quirk, associating it with Endeavor's cruelty. Toya was later presumed dead in an accident, intensifying Endeavor's training. Shoto entered U.A. High School via recommendation but maintained a cold, trauma-fueled demeanor. He initially dismissed classmates and favored solitary action, incapacitating villains alone during the U.S.J. incident and threatening them for information. His arrogance and resemblance to Endeavor's hostility caused Inasa Yoarashi to resent him. Shoto's hero costume featured ice plating over his left side, symbolizing his rejection of Endeavor's fire. During the U.A. Sports Festival, Shoto confronted Izuku Midoriya, declaring he would win using only his ice Quirk. Midoriya provoked him to embrace his full power, reminding him of Rei's encouragement. This triggered Shoto's first use of fire in battle since childhood. Afterward, he reconciled with Rei, visiting her regularly, and accepted his fire as his own. He chose to intern at Endeavor's agency for practical growth but clarified this did not mean forgiveness. Shoto gradually became more sociable, though reserved. He developed teamwork skills during the provisional license exam and subsequent missions. His costume evolved to integrate temperature-regulating gear, reflecting his acceptance of both Quirks. In the Paranormal Liberation War, Shoto learned his brother Toya was alive as the villain Dabi. He acknowledged their shared hatred for Endeavor but resolved to stop Toya himself. After the war, he offered Endeavor support to confront Toya together, though he later insisted on facing Toya alone to ensure Endeavor fought All For One. Eight years after the Final War, Shoto graduated as the No. 2 pro hero. His scar faded slightly, and his costume retained its signature T-shaped stripe. He maintained a cautious relationship with Endeavor, emphasizing that forgiveness required ongoing effort while demonstrating concern for his father's safety.