Vs. Hero Killer Arc:
Prior to his official appearance in the series, Gran Torino had originally sent a nomination request letter to U.A requesting Izuku Midoriya to be his trainee for his field training assignment after seeing him be All Might's successor as the next wielder of the "One For All" quirk during the U.A Sports Festival. All Might informs Midoriya about said nomination request but warns him about Gran Torino's intense training method during the time that Gran Torino was Toshinori's homeroom teacher back in his days as a student in U.A.
Some days later at the start of the field training assignment, Midoriya goes to Gran Torino's home only to find the old man lying face flat on the floor with what appears to be blood on floor below him, terrifying Midoriya thinking the old man might be dead.