| Name | Brennan Sorrengail |
|---|---|
| Age | 29–30 years |
| Species | Human |
| Status | Alive (presumed dead in Fourth Wing) |
| Quadrant | Riders Quadrant (graduate), Basgiath War College |
| Rank/Title | Lieutenant Colonel |
| Signet | Mending |
| Eye Color | Amber |
| Hair Color | Reddish-brown |
| Dragon Bond | Marbh (Orange Daggertail) |
| Family | Asher Sorrengail † (father), Lilith Sorrengail † (mother), Mira (sister), Violet (sister), Xaden (brother-in-law) |
| Love Interests | Not listed / unknown in canon |
| Appears in | Fourth Wing (2023), Iron Flame (2023), Onyx Storm (2025) |
Biography
Fourth Wing
Brennan Sorrengail is a dragon rider, lieutenant colonel, and one of the central figures in the Revolution against Navarre’s hidden war with the venin. He is the eldest child of Lilith and Asher Sorrengail, and the older brother of Mira and Violet Sorrengail. Long before Violet enters the Riders Quadrant, Brennan is remembered by his family as brilliant, kind, protective, and almost impossible to live up to.
Before his presumed death, Brennan trained as a rider at Basgiath War College, where he bonded with Marbh, an orange daggertail dragon, and manifested the rare signet of Mending. He became known as an exceptional rider and a gifted strategist. During his time at Basgiath, he also wrote the “Book of Brennan,” a survival guide that later becomes one of Violet’s most important resources when she is forced into the Riders Quadrant.
Brennan was officially believed to have died during the Tyrrish Rebellion. Reports claimed that he was killed during the Battle of Aretia, and his death devastated the Sorrengail family. For years, Violet and Mira believed their brother was gone, and even the mention of Brennan or his dragon became painful within their household. His supposed death also became part of Navarre’s wider version of history, hiding the truth about Aretia, the Revolution, and the venin threat.
In reality, Brennan survived. After the rebellion, he secretly joined the Revolution and lived under the surname Aisereigh, distancing himself from the Sorrengail name and the enemies connected to his mother’s position in Navarre. In Aretia, he became a ranking member of the Assembly and helped organize the rebellion’s efforts from Riorson House. His role combined strategy, healing, leadership, and the difficult work of preparing riders and gryphon fliers for a war most of Navarre still refused to acknowledge.
At the end of Fourth Wing, Violet discovers that Brennan is alive after she is brought to Aretia, poisoned and badly injured following the Battle of Resson. Brennan mends her wounds and welcomes her to the Revolution, turning one of Violet’s deepest griefs into one of the greatest shocks of her life. His survival changes everything she thought she knew about her family, Navarre, and the rebellion.
Iron Flame
In Iron Flame, Brennan becomes an important guide for Violet as she learns the truth about venin, wyvern, the wards, and the Revolution. He remains based in Aretia for much of the conflict, helping lead the Assembly and coordinate the riders who defect from Basgiath. His relationship with Violet is affectionate but complicated because his decision to remain hidden cost his sisters years of grief.
Brennan is later reunited with Mira, whose reaction is far more explosive. While Violet is shocked and emotional, Mira is furious that Brennan allowed them to believe he was dead for years. The three Sorrengail siblings eventually find themselves on the same side of the war, but their reunion is shaped by grief, anger, loyalty, and the enormous weight of everything Brennan kept secret.
During the later events of Iron Flame, Brennan plays a crucial role in the fight to restore Basgiath’s wards. His mending signet allows him to repair the damaged wardstone, though the effort nearly pushes him to the point of burnout. When Lilith Sorrengail sacrifices herself to raise the wards, Brennan is forced to confront the mother he resented, the lies that shaped their family, and the complicated love that still bound them together.
Onyx Storm
By Onyx Storm, Brennan remains one of the Revolution’s most valuable leaders. His skill as a mender makes him almost irreplaceable, but his true importance goes beyond his signet. He is a tactician, commander, older brother, and living proof that Navarre’s official history cannot be trusted.
Physical Description
Body & Build
- Tall and physically strong, with the build of an experienced rider
- Sharp facial features with little softness to them
- Has his father’s nose
- Known for a deep voice and a commanding presence
Hair
- Reddish-brown hair
- His curls are cropped close to his skull rather than falling over his forehead
Eyes & Distinctive Features
- Amber eyes
- Small lines at the edges of his eyes
- A dimple appears in his cheek when he smiles
- Has a rune-shaped scar on his palm
Clothing & Gear
- Typically wears rider leathers and military clothing suited to his rank
- Associated with the practical, disciplined appearance of a commander in the Revolution
Personality
Brennan is intelligent, composed, and highly strategic. He is often described through the impact he has on others: as a brilliant rider, a good man, a gifted tactician, and an older brother whose memory shaped both Mira and Violet long before his return. He is calm under pressure and tends to focus on solving problems rather than drawing attention to himself.
His kindness is one of the traits Violet remembers most clearly. As children, Brennan helped her wrap her joints and took time to care for her when she was vulnerable. Even after years in hiding, that protective instinct remains central to who he is. He wants to keep his sisters safe, even when his choices hurt them or force him to keep painful secrets.
Brennan is also pragmatic. Unlike Violet, who often acts from a strong personal sense of justice, Brennan tends to prioritize the survival of the Revolution and the larger war effort. This can make him seem distant or frustrating, especially when he makes decisions that protect the cause at the expense of emotional honesty.
Despite his serious role, Brennan still shows warmth around his sisters. He can tease Violet, bicker with Mira, and briefly reveal the older brother they both lost. These moments make his return more complicated: he is still Brennan, but he has also become a commander shaped by war, secrecy, and years of impossible choices.
As a leader, Brennan is disciplined and work-focused. He is less interested in praise or celebration than in getting things done. His position within the Assembly shows that others trust his judgment, and his ability to operate as both healer and strategist makes him one of the Revolution’s most important figures.
Powers
Lesser Magic
Through his bond with Marbh, Brennan can channel lesser magic like other bonded riders. This includes abilities such as locking and unlocking doors without touching them, moving with preternatural speed, manipulating mage lights, powering ink pens, and placing runes.
Although lesser magic is common among bonded riders, Brennan’s use of magic is especially valuable because of his discipline and experience. As a commander and mender, he often uses his power in situations where precision, timing, and restraint matter as much as raw strength.
Signet
Mending: Brennan’s signet allows him to fix, restore, or return things to their original state. His ability can be used on objects, structures, and living bodies, making him one of the rare riders capable of healing severe physical injuries.
Brennan can mend broken bones and damaged structures, and his power is strong enough to help repair the wardstone at Basgiath. This makes him one of the most valuable menders of his generation. If he had remained publicly loyal to Navarre, he likely would have been celebrated as one of the greatest known menders.
However, his signet has limits. Brennan cannot mend magic itself, and he cannot restore something that has been completely severed or removed. His power also comes with the risk of exhaustion and burnout, especially when he attempts large-scale or life-threatening mending.
Abilities
Languages
Brennan is multilingual. He learned Tyrrish from his father, speaks Krovlish, and is fluent in the common language of Navarre. His language skills reflect the intellectual side of his character and the influence of his father’s teachings.
Strategy
Brennan is a skilled strategist and one of the Revolution’s key tacticians. He helps plan operations, organize defenses, and coordinate riders and gryphon fliers in Aretia. His nickname as a tactician reflects his ability to think clearly under pressure and make difficult decisions during war.
Poison Knowledge
Brennan has extensive knowledge of poisons and toxins. This makes him useful not only as a healer, but also as someone who understands how poison can be used, identified, and countered in dangerous situations.
Leadership
As a lieutenant colonel and member of the Assembly, Brennan holds real authority within the Revolution. He is trusted to lead riders, make strategic decisions, and speak on behalf of the rebel leadership. His leadership style is practical, controlled, and focused on survival.
Combat
As a trained rider and Basgiath graduate, Brennan is capable in combat both on the ground and in the air. While his mending signet often places him in a healer’s role, he remains a soldier and commander in an active war against venin and wyvern.
Relationships
| Violet Sorrengail | Violet is Brennan’s youngest sister. As children, Brennan helped care for her and supported her when her body made ordinary training more difficult. His “Book of Brennan” later helps Violet survive her first year in the Riders Quadrant, even while she believes he is dead. Their reunion in Aretia is one of the major turning points in Violet’s story. Brennan becomes a mentor and protector to her, though their relationship is complicated by the years he spent hiding the truth. |
|---|---|
| Mira Sorrengail | Mira is Brennan’s younger sister. She grieves him deeply after his presumed death, and her reaction to learning he is alive is far more angry than Violet’s. Mira feels betrayed that Brennan allowed his family to suffer without knowing the truth. Despite this, the siblings still love each other, and their dynamic keeps much of its old sharpness, loyalty, and bickering. |
| Lilith Sorrengail | Lilith is Brennan’s mother. Their relationship becomes deeply strained after Brennan learns more about Navarre’s lies and the choices made after his presumed death. Brennan resents her for the role she played in upholding the system he now fights against. Their reunion is emotional, but he does not fully reconcile with her before her sacrifice at Basgiath. |
| Asher Sorrengail | Asher was Brennan’s father and an important influence on his early life. He taught Brennan Tyrrish and helped nurture his interest in language and knowledge. Brennan’s connection to his father is reflected in both his intellectual nature and his grief over what his family lost. |
| Xaden Riorson | Brennan and Xaden are both important figures within the Revolution, though their relationship is not always simple. Xaden keeps Brennan’s survival secret until Violet discovers the truth, and Brennan often worries about the danger surrounding Violet because of Xaden. Despite tension between them, Brennan respects Xaden’s role in the rebellion and works alongside him when their goals align. |
| Naolin | Naolin was connected to Brennan during the events surrounding Brennan’s presumed death. He was believed to have tried to save Brennan and died in the process. The exact nature of their relationship remains partly unclear, but Brennan’s reaction when Naolin is mentioned suggests that the connection may have been deeply important to him. |
Dragon
Marbh
Brennan is bonded to Marbh, an orange daggertail dragon. Through Marbh, Brennan can channel lesser magic and manifest his signet of Mending. Their bond allows Brennan to function as one of the Revolution’s most valuable healers, commanders, and magical assets.
Marbh was wounded during the events surrounding Brennan’s presumed death, but both dragon and rider survived. Their survival became one of the secrets hidden beneath Navarre’s official account of the Tyrrish Rebellion. Although the books reveal limited details about Marbh’s individual personality, his bond with Brennan is central to Brennan’s power and continued role in the Revolution.
