When Shoto was scorched; he was around five years old. Rei Todoroki, the mom, begged Endeavor to cease their son’s rigorous training. Rei pleaded with him to end. He is just five. Shoto is approximately five years old because he appeared to be about the same age in the throwback panels of him being burned.
As during the Athletics Festival Arc, Shoto and Deku square off in volume 39. Shoto urges Deku to take charge and then use the left side after growing impatient with him for being cautious and not employing all of his skills. This brings back memories of Rei defending Shoto from Endeavor while his mother remarked, “He’s just 5.”
It’s safe to presume that Shoto remained five years old while his mom torched him because the panels depicting him getting burned appear to be about the same age as the ones in this flashback.
Shoto Todoroki’s burns—how did they occur?
Shoto started to appear to his mother as just an expansion of Endeavor as she grew increasingly depressed by Endeavor’s treatment of their household. All of the dad’s dreams and ambitions were invested in Shoto’s accomplishments. In a rage, the Todoroki mother finally lost it and threw boiling hot water in Shoto’s face.
Endeavor admitted Shoto Todokoki’s mom to the doctor. She has been a patient at the institution for an illimitable amount of time; this is more of a lengthy mental facility.
Guests are invited, and despite their altercation, Shoto has taken the opportunity to mend fences with his mom. He believes his father is to blame for driving her to such extremes.
That should do it, then. When Shoto was wounded, he was around five years old. In Chapter 39, his mom refers to him as being five years old when he was hurt.
Other Thoughts
While his brother Touya passed away, Shoto was also around 5. Shoto is depicted in manga panels yearning to spend quality time alongside his bigger brother as he plays outdoors with the other brothers. Still, Endeavor keeps dragging him back into training.
The scar on Shoto’s arm is not a cold burn. Boiling water was dumped on his head, causing the burn. Todoroki’s left eye is also not blind, notwithstanding burn injuries towards that side of the face. Todoroki’s wounds have left him blind, yet neither the manga nor the anime acknowledges this.