Liam was born in Plymouth, Massachusetts, to a family of Irish immigrants, the O'Briens. The O'Briens struggled on their farm, and later moved to New York. Liam joined his father, who worked for a shipping merchant, and later joined his father, loading England-bound ships. It was in this business where he met Shay Cormac. Immediately the two became best friends, and Liam often looked after Shay, due to his rough living conditions.
After a few years, Liam's employees were growing in wealth, even when his fellow workers were unpaid and mistreated by the authorities. These tensions grew to a breaking point, and Liam recruited several co-workers in a plot to rob the employer and distribute the money among each other. Though, in the middle of the heist, they got caught, and in an act of self-defense, Liam killed a man. But, in an attempt to protect Liam, his father took the blame, and was executed .
Joining the Assassin Brotherhood
Later on, Liam moved from one job to another, and robbed in order to help his mother, who was aging. Liam continuously drifted from his friends, including Shay. But in 1738, He met master assassin, Achilles Davenport, who tasked him with small errands, and over time, Liam looked to Achilles as a mentor and became influenced by the Assassin order. Achilles accepted Liam as a member and thus, Liam was his first student. Liam helped Achilles recruit other members of the brotherhood, including Hope Jensen, Kesegowaase, and Louis-Joseph Gaultier, Chevalier de la Vérendrye.
In 1748, Shay lost his father, and reconnected with Liam, who helped him get back on his feet and recruited him to the brotherhood. because of this, Liam was tasked by Achilles to look after Shay, just like he did long ago.
Assassin Expedition and Liam's death
Years later, The assassins found two objects, the Voynich Manuscript and Precursor box, which could lead to a destructive piece of Eden. When Shay was sent to find it, it destroyed the city, causing him to betray the assassins and join their enemy's, the Templars. When Liam and Achilles went to find it again, it was found out that Shay and Haytham Kenway had pursued and disturbed the object. Vengefully, Liam attempted to shoot Shay, but was stopped by Achilles, and knocked over the artifact. Because of this, the area destabilized and began to collapse around them.
Liam took the manuscript and fled the Temple, but was followed by Shay. Liam reveled to Shay that Chevalier Had taken the precursor box and hid it where the Templars could never find it. Eventually, Shay cornered Liam at a cliff, and the two fought. However, the cliff side collapsed and both fell. Shay suffered minor wounds, but Liam's were more fatal. He questioned why Shay joined the Templars. Shay replied "To save the World." to which Liam sarcastically hoped that it would be a good one, and life slipped away from him. Respectively, Shay pulled Liam's hood over him.
Personality and Skills
Liam is a patient and respectful character. He didn't hesitate to intervene between Shay and Chevalier fighting. He is seen as a more peaceful and calm character, but would not hesitate to sacrifice his friendship for the sake of fulfilling the duties of the brotherhood. He also believed in the creed and admired fellow assassin mentor, Adewale. He is a very skilled assassin, a proficient marksman and swordsman. He was also capable of defeating a number of colonial soldiers, and had some knowledge of sailing, acting as the first quartermaster of Shay's ship, the Morrigan. Liam is also a skilled freeruner, being able to perform a leap of faith. He is a skilled man in the field of weapons, equipped with two hidden blades, a sword, and, his preference, Dual pistols.