- "As far as the world is concerned I have already served my death sentence."
- —Steven Mercier (Ace Combat:Electrosphere Rebirth)
Born in North Point, Steven lived a simple life untill his parents were killed when Ulysses fell. After the death of his parents, Mercier was sent to an orphanage where he was adopted by a member of the Falcons of Dawn. When this member brought him back to thier base in Belka, his quickly became Oswald Baermann's "favorite" out of the child soldiers. Though not Belkan born, he was able to climb through the ranks and eventually became a pilot in the FODMD (Falcons of Dawn "Mercenary" Division.)
The Haydon Incident
The Ravalkin Conflict
Known as Sandstorm 10 during the Ravalkin Conflict, he joined the war under a false I.D. that was to lable him as a mercenary but due to an error made him seem to join as a rookie pilot. Using his experience as a pilot of experimental planes he soon became an ace as he fought the Ravalkin military throughout Silvelkia. (Further info as the story progresses.)
The New World
12 years later, under the TAC name "Hunter," Hunter one became the leader of the Hunter Squadron created by allied nations to fight against the group known as "The New World", but when Osea declared war on Belka the alliance between Osea and the other nations soon fell apart and Hunter One and the rest of his squadron became mercenaries. Later on Hunter One created a group known as "The Knights of the Old World" to fight "The New World". It was during this time that Hunter One recived the nickname "Wing Breaker". Eventually Hunter One made to the base of "The New World" and sacrificed himself by colliding into the "Rebirth" missle. It was unknown if he was still commanding "The New World" at the time of the creation of the Hunter Squadron or why it was created to begin with. He died on June 25th, 2025.
Hunter One is later found alive in the year 2060, having gone through Rebirth along with legendary ace pilot "Cipher" he and his squadron fight General Belka throughout Strangereal trying to reveal the truth about the war.
In Ace Combat: Double-Edged, At one point in history, Steven and his friend Roy Harding would come across a time machine due to the distortions in Time and Space and would go on a time-travel trip that would be known as "Steve and Roy's Excellent Adventure" to save multiple worlds from the effect of Spility, the cause of the timeline becoming absurd as it was in Ace Combat 52 Pickup