Lorcan has a massive, muscular build. He has onyx eyes and matching shoulder-length hair and cruel, granite-hewn facial features. It is mentioned by Elide that when he smiles it makes him appear younger and more handsome.
He is a vicious, ruthless, accomplished warrior who has no qualms about using any means necessary to execute his orders. Rowan Whitethorn describes him as wicked and cunning; according to Aedion Ashryver, the tales surrounding Lorcan involve much glory and gore, but mostly gore.
After meeting Elide Lochan, Lorcan's personality softens and he becomes more caring.
Centuries prior to the events of the series, Lorcan offered Rowan Whitethorn the choice to join his band of warriors. This eventually led to Rowan swearing the oath to Maeve.
In Queen of Shadows it is revealed that two centuries ago Maeve ordered Lorcan and Rowan to obliterate a city of apparently corrupt and evil residents.
When Mistward is besieged by the Valg, Lorcan arrives with the rest of Rowan's cadre to help. When Aelin is attacked by the three Valg princes, Rowan is restrained by Lorcan and Gavriel to prevent him from rushing to help her. Lorcan tries to convince Rowan to let it go, as Aelin is surely dead. Rowan manages to break their hold and runs to Aelin while Lorcan swears behind him.
After the Valg are defeated, Lorcan leaves at dawn the following day. Gavriel informs Rowan of his departure, and says that Lorcan said to tell him goodbye. Rowan sees through the lie.
Later in the book when Rowan and Aelin travel to Doranelle, Maeve asks Aelin for the location of the third Wyrdkey. When she refuses to answer Maeve orders Rowan to tell her, but he doesn't know as Aelin never shared the information with him. Maeve has Lorcan and Gavriel whip him to compel Aelin to tell her where the Wyrdkey is. Lorcan takes no pleasure from harming Rowan, and keeps a blank expression as if he has done it before. He watches while Aelin displays her power to Maeve, and makes no move to stop her from approaching Rowan. He witnesses Rowan being released from his blood oath and swearing it to Aelin.
Rowan reveals to Aelin that Lorcan is in Adarlan. He details how he tracked Lorcan to Rifthold, and reflects on how Lorcan is the strongest male in the Fae realm, equal only to him. He wishes he could kill Lorcan for not helping Aelin against the Valg Princes, and promises to kill him if he makes a move against her. They assume that he was sent by Maeve to look for the Wyrdkey.
Lorcan is tricked by Aelin into entering a den of Valg commanders and a Wyrdhound. She saunters away while he fights them. He catches up to her and slams her into a brick wall, pinning her against it. He is angry about the trick and threatens to kill her, but she holds a knife to his groin and warns him against it. He releases her and moves away, and taunts her about Rowan sleeping with her. They exchange insults until Rowan arrives and holds a knife to Lorcan's throat. Rowan tells him to talk, and Lorcan reveals that if he dies Maeve will offer aid to the King of Adarlan. Rowan releases him and goes to Aelin. Lorcan explains that Maeve let them walk out of Doranelle, and taunts Rowan, calling him a fool for allying himslef with Aelin. He threatens Aelin, saying that he'll be waiting when she trips up, and she tells him that one day she will claim the debt he owes for whipping Rowan. Lorcan leaves.
Lorcan travels with Elide. He shields her as Aelin unleased her power on an army of ilken. In the end it was discovered that he betrayed Aelin and led Maeve to capture her, using his powers. However, Maeve stripped him of the blood oath and titles, leaving him in dishonour. Afterward, Lorcan vows to go with Rowan to rescue Aelin, out of guilt and desire to redeem himself in Rowan and Elide's eyes.
- In Heir of Fire, Maas describes Lorcan as a demi-Fae. This is unusual as Maeve only seems to show favour of those who are full Fae.