“Today is a day of joy and sorrow for the Brotherhood. Gammorin was a traitor, a murderer, and a deceiver, yet he was a Paladin. His brave deeds once brought much hope to the wasteland. Yet, something happened to him when the Great Storm ripped his airship from the Convoy and crashed it to the ground. From that moment, Gammorin was born, and the Brotherhood lost its favored son.”— Dekker
Some time after their departure, Gammorin's mutants were pursued by Brotherhood of Steel airships. While most of them ended up in the vicinity of Chicago, far from Gammorin's forces, one of the zeppelins crashed north of the mutant encampment. The leader, Paladin Latham, challenged Gammorin to a single unarmed combat and, to the surprise of everyone, killed the mighty mutant. As he defeated the previous chieftain, the super mutants expected him to become the new leader of their army. Latham suffered a head injury during the combat, and throughout the years, he grew more and more insane, even though he managed to organize the mutant forces into an army nearly as powerful as they had been during the Master's reign. He begins to see the super mutants as his own people, however, he hasn't forgotten the Brotherhood and his past.
When Latham's forces encountered the Calculator's robots from Vault 0, he swore an oath to destroy the cybernetic menace. By that time, he assumed the name "Gammorin", after the super mutant chief he had killed. Gammorin's mutant scientist ran extensive research in order to find a cure to super mutant sterility. However, his laboratory in Jefferson City was taken or destroyed by a splinter faction of the Brotherhood of Steel from the Chicago area, who believed it to be a weapons manufacturing plant. Eventually, Latham/Gammorin and his forces were defeated by the Brotherhood.
When the Warrior and his squad came to meet Gammorin, the former Paladin speaks of the Elders' foolishness and blindness to a new menace from the west, which only his mutants are able to fight. At the end of the fight, being mortally wounded, his last words were that all he had done was in the name of stopping the coming threat. Upon his death, many of his super mutants soldiers were allowed to join this Brotherhood to fight against the robots. Research into a cure for the super mutants' sterility was continued by the Brotherhood, but in the end was unsuccessful.
Latham/Gammorin is the head of the Midwestern super mutant army and very much a boss character - his incredible stats, skills, resiliency and critical chance make him a very dangerous foe, especially in the close quarters of the Osceolla bunker. Despite all of his stats, however, his choice of a Tommy gun as a main weapon makes him a terrible ranged fighter, with the .45 slugs rolling off any decent suit of armor like rain drops.
"Excellent work, Warrior. Today is a day of joy and sorrow for the Brotherhood. Gammorin was a traitor, a murderer, and a deceiver, yet he was a Paladin. His brave deeds once brought much hope to the wasteland. Yet, something happened to him when the Great Storm ripped his airship from the Convoy and crashed it to the ground. From that moment, Gammorin was born, and the Brotherhood lost its favored son." – Dekker
"Welcome brothers. Welcome. What a fine bunch of soldiers I see before me. If only the West Coast Elders could see you. They would have finally agreed with us about sharing the Brotherhood's wealth of education and technology. But I digress. Do you believe you can stop the Menace from the West? Your eyes give you away "brother." They tell me you don't even understand who or what the Menace is. The Elders have always been blind to what is not in front of them. But it ends here. The General is not here for you to save, I'm afraid. And you cannot save me... or yourself. Now, show me what you've learned!"
"I did not sacrifice my very identity to be beaten by those I strive to save! Ask yourself what you will gain by killing me?! Judge me not by my actions but by my goals! This undead enemy will not stop until all life has been extinguished! Why can't you see that? Why?!!"