A noble war hero
Sir Gregor is played by Ian McShane.
Sir Gregor is the most famous and greatest hero of all time of the area that Laurence, Lyra and Thomas are from.
Sir Gregor was the hero that Laurence dreamed of squiring for. Laurence was too down-to-earth to even think that he could ever become as great as Sir Gregor, but ambitious enough and enough of a dreamer to imagine himself as his squire.
That never happened, but Laurence was deployed to the same unit as Sir Gregor in the 3 year war right from the start. That unit was the vanguard of the army, going far into enemy territory to try and establish more ground. Laurence got the “honor” of being deployed there since he had been in the army for 3 years (from the age of 18) and since he had been a squire a lot longer.
This parted Laurence and Thomas, which was originally something Laurence fought against but when he realized how dangerous the territory he was going to he didn’t want to take his then 14 year old brother with him into the fray.
Sir Gregor was anything but the knight that the stories said he was, not a hint of honor or a gentleman in him. Sir Gregor stabbed men in the back, attack enemy camps during the night as the enemy slept, had a caravan of whores follow the unit for him and his men and much much more in that caliber.
When Laurence dared question his backstabbing mentality Sir Gregor took it upon him to publicly shame him in front of the whole unit.
That was early in the war, but about half way through it Laurence and Sir Gregor became friends and Laurence even ended up as Sir Gregor’s confidante, during late nights as Sir Gregor would try to drink himself to sleep. His conscious would not let him fall asleep without confessing his sins and drinking until oblivion came calling.
This experience made Laurence lose his extreme faith in knights and any aspiration in the matter. He saw them for the extremely flawed individuals they are, rather than the monsters he saw them as in the beginning of the war or saintly figures he had originally envisioned them as.
Sir Gregor made Laurence long to become a farmer, for the first time in his life.