Laurentius is first encountered during the search for the missing Frixio. Buscarron suspected him as a possible informant to the Garleans, due to his increased spending at his tavern. Since he was a Wood Wailer rather than a common merchant, this looked suspicious. With the Adventurer suddenly encountering Garleans outside Buscarron Druthers, he put two and two together and asked that Laurentius be investigated. Laurentius tried brushed off questions, but was eventually caught red-handed. With the surprising aid of Redbelly Bandits and Coeurlclaw Poachers, Laurentius realized that Buscarron was responsible and decided to turn himself in. He asks the Adventurer pass along a message to the tavernkeep - "thank you."
Later he is seen again in Gridania as a volunteer for Alphinaud's new Grand Company, the Crystal Braves. He declares his intent to start a new leaf as one of the first recruits. After Alianne failed to show up at the designated meeting point outside Nanawa Mines where her letter directed the Adventurer to meet, he claimed that she hasn't been seen at this side of Central Thanalan. As the Adventurer turned to leave, he eyed the Warrior of Light suspiciously and began speaking something into a linkpearl. He is seen among the traitorous Crystal Braves with Ilberd when Teledji Adeledji accuses the Scions of the Seventh Dawn of assassinating Nanamo Ul Namo.
When the Warrior of Light, Alphinaud, and Yugiri Mistwalker attempt to rescue Raubahn, who has been taken to Halatali for execution, Laurentius confronts them in battle alongside Ilberd and Yuyuhase, and flees upon defeat.
Later, as the Griffin launches his false flag operation on Baelsar's Wall, Laurentius is seen wearing an imperial disguise. Solemnly, he orders a swarm of magitek Armored Weapons to massacre the hired soldiers as part of Ilberd's plot to summon a primal.
After the liberation of Ala Mhigo, Raubahn informs the Warrior of Light that Laurentius and Yuyuhase had been found and arrested. He asks their opinion of what should be done with them, and says that he will bring their opinion into consideration when they are brought before trial.
Laurentius is a male midlander Hyur with dark-brown hair and distinguishing sideburns. He initially wears the common uniform of the Wood Wailers, a brown toadskin leather jacket, but eventually wears the ultramarine uniforms of the Crystal Braves.
During the battle at Baelsar's Wall, he is seen disguised as an imperial soldier.
Laurentius is corrupt and weak-willed, often accepting bribes and carelessly displaying the sudden wealth. He seems repentant after being defeated by the Adventurer, and later volunteers to join the Crystal Braves. However, he falls to his old ways, siding with Ilberd and Yuyuhase in their treachery.
Unlike the other two, he seems to retain a measure of a moral compass. As he follows out Ilberd's orders while disguised, he expresses a very grim and regretful expression before ordering the Armored Weapons to massacre the Resistance fighters as part of the sacrifice.
Laurentius is fought as a instanced boss during the Main Scenario quest Nouveau Riche. The player must defeat him and all his Garlean contacts with the aid of local bandits and poachers. Laurentius is faced again during the Main Scenario Quest Keeping the Flame Alive in Final Fantasy XIV: Heavensward.
In Final Fantasy XIV: Shadowbringers, Elidibus challenges the Warrior of Light to reenact their journey, he creates simulacrums of many of the opponents they faced in the past to fight them. One of these is Laurentius, who fights the Warrior of Light alongside simulacrums of Ilberd and Yuyuhase.