|Date of birth||uncertain, possibly around 0005|
|Familiar||The Liese Twins|
|Japanese name||ギル・グレアム |
|Voiced by||Chou Katsumi|
Gil Graham (ギル・グレアム Giru Gureyamu), commonly known as Admiral Graham, is an aging Englishman and one of the few people from Earth with a magical aptitude. Aria and Lotte Liese, his twin catgirl familiars, used to be Chrono Harlaown's teachers in close combat and magic.
Gil was introduced to magic when he saved a Bureau clerk 50 years before the start of A's, much like Nanoha saved Yuuno Scrya, and subsequently moved to Mid-Childa. He feels responsible for an incident 11 years in the past in which Clyde Harlaown died while attempting to transport the Book of Darkness, and has thus dedicated himself to sealing it. At some point after Hayate Yagami's parents' death, he started supporting her financially, claiming to be a friend of her father's.
Gil is first seen meeting with Nanoha, Fate and Chrono for an interview related to Fate's trial. He tells Fate that as long as she does not betray her friends, he will not put any restrictions on her movement.
Towards the end of A's, Gil is revealed to be the perpetrator behind the entire Book of Darkness Incident of 0065. Upon realizing that Hayate Yagami was to become the next master of the Book of Darkness, he began posing as a friend of young crippled orphan's father, planning for her to awaken the Book of Darkness. When the Wolkenritter then began to fill the pages of the Book by stealing other mage's Linker Cores, he dispatched Aria and Lotte, disguised as masked men, to make sure the Book was filled successfully. According to Gil's plan, the Wolkenritter were to be the last sacrifices for the Book, so Gil sent Aria and Lotte to absorb their Cores. After killing Signum, Shamal, and Zafira, the Liese twins assumed the appareance of Nanoha and Fate and summoned Hayate to the roof before killing Vita in front of her, causing her to go berserk and activate the Book.
The next step in Gil's plan was to use the Durandal, a highly potent Storage Device specialized in freezing magic, and freeze Hayate and the Book in another dimension forever. However, Chrono saw through the scheme and placed Gil under arrest. Even so, Gil attempted to convince the young man to carry on with his plan, thus stopping the Book for good, and handed Durandal over to him. In the end, however, The Book of Darkness Incident was resolved after Hayate managed to regain partial control over the artifact and the Asura destroyed its corrupted self-defense mechanism with Arc-en-ciel.
In the aftermath, Gil resigned from TSAB. He was not charged for hacking into TSAB systems or hindering the investigation, and plans to tell Hayate the truth about his scheme when she is old enough to leave home. He is last seen living peacefully with Aria and Lotte, receiving a photo of Hayate and her Knights six years after the conclusion of A's.
Though only for a brief moment, near the end of episode 13 of StrikerS, a photo of Gil Graham with Lotte and Aria in their cat forms can be seen as Hayate passes through a photo album on her desk, reminiscing about the past.