Born 73 After Aegon's Conquest Ser Thorin Stark, knighted at the age of 10 and 1 namedays and was appointed as Kingsgaurd at the age of 10 and 9 namedays was Kingsgaurd for 4 regency's. Near the end of King Jaehaerys reign he was appointed Lord Commander for a short time when Ser Ryam Redwyne was Hand Of The King and then was appointed Second in Command for 30 years during Jaehaerys and Viserys reign and was appointed lord commander during Rheanyra's short reign and was reappointed again to lord commander after that during Aegon the Thirds reign. He had died in 157 AC at the age of 80 and 4 name days, only days after Aegon the Third had died.
It is documented that Ser Thorin had killed more men in arms in history except for those riding dragons of course with over 1000 confirmed kills over his lifetime. It had baffled many maester decades later as no one man could possibly kill that many. But many Lord Commanders know that most of his kills came from the dance and the conquest of the Stepstones.
He had kill over 5 disgraced Kingsgaurd, Ser Criston Cole on the battle of Butchers Ball south of the god's eye fought Ser Thorin Stark it was said that the battle only lasted a few minutes only prolonged because of interference from Criston's side.Ser Rickard Thorne had attempted taking Prince Maelor to Oldtown for safety but Ser Thorin arrived at bitterbridge and slew Ser Rickard Thorne before he could ever make it. The Prince Maelor was given to Queen Rheanyra at kingslanding who ordered his death. Ser Gyles Belgrade was executed by the Lord Commander Ser Thorin Stark by order of Lord Cregan Stark. Willas Fell was killed in a Duel by accident during a jousting tourney in Aegon The Thirds regency though it was rumored that he pierced him with his lance on purpose but nobody said anything to prove it. Ser Mervyn was killed by Ser Thorin in a duel in the stables of kingslanding after he killed two of their sworn brothers.
Before the Dance of Dragons he was involved in the conquest of the stepstones where he and Prince Daemon boldly acted to surrender arms to Craghas Drahar the crab feeder but when his guard was down they was able to slay him in his own tunnels he ran to when daemon's dragon arrived.
Nearing the end of Aegon the Thirds reign he had squired and knighted Aemon "The Dragonknight" Targaryen. It was recorded when Aemon and Thorin dueled that Thorin was taking it easy on him when Aemon duel him the last time in 157 AC only a month before he had died. Aemon after he had dueled the greatest Lord Commander of the Kingsgaurd "I never thought the Old Bloody Cloak could still move like that."
Aemon announced to Daeron I small council he had died in his sleep. While he was transported to winter fell many lords who had fought with him in battle during the dance offered condolences to the Stark Family though barely any of the current stark family knew him closely as the Targaryen family knew the old Commander.
It was said by Daeron I to Aemond "There goes the greatest protector of House Targaryen, there he goes to a damp and dark place where House Stark hasn't housed him in decades."
In one of King Viserys II Accounts to the Lord Commander of The Kingsgaurd when he said that The Old Bloody Cloaks deeds weren't really that much of a knight. "That Old Man has protected House Targaryen for almost a century I'd be best not to disrespect a man who tried his hardest in the interest of my mother Queen Rheanyra for your sake." Many years even after his death many Targaryens still believed he was their greatest protector in their darkest time. Especially during Aegon the Thirds rule as many of the assassination attempts were thwarted by him alone.
Cregan Stark to Thorin Stark "You are always welcome back home in winterfell grandfather." Thorin Stark - "I'm sorry my grandnephew but house Targaryen especially little Aegon III will need me when you leave." Cregan Stark - "yes it's unfortunate my children won't get to see you in person but the North Remembers." Thorin Stark - "When the snows fall and the white winds blow, the lone wolf dies but the pack survives" - A Talk between Old Wolves
Thorin Stark - "I'm sorry little Egg that I couldn't save your mother and your brothers." Aegon III - "You tried your best during a chaotic time that could've been avoided" - Thorin Stark to Aegon III during a private meeting