Pre-Super Genesis Wave
After moving to Mobotropolis at a young age, Antoine D'Coolette began training as a cadet to one day become a solider in the Kingdom of Acorn's Royal Army. However, when Doctor Ivo Robotnik began his takeover of the city, Antoine was forced to flee with his friends and family into the Great Forest for safety. Antoine's father Armand D'Coolette stayed with his troop to fight through the chaos caused by Robotnik's forces and was later assumed that he died in battle (though it was eventually revealed that Armand was Roboticized). Antoine's mother Marie was devastated and Antoine took to wearing his cadet uniform as a testament of loyalty to his father, although he had yet to finish his training.
Years later, Antoine became one of the founding members of the Knothole Freedom Fighters and a recurring victim of Sonic's jokes due to his arrogant personality. Antoine is also quite cowardly, sometimes running away from danger instead of fighting it, although during his many adventures alongside his teammates, Antoine gradually grew more brave, if still nervous at times.
Feeling as if he was expected to marry into the royal family Acorn, Antoine tried to find romance with Princess Sally Acorn, but his advances on her were rejected in favor of Sonic the Hedgehog. Antoine would finally find romance with Bunnie Rabbot who he later married despite attempts by Antoine's evil doppelgänger Patch to ruin their relationship.
During a mission to protect former King Elias Acorn and his family from the Eggman Empire, Antoine grabs into Metal Sonic who has latched onto Elias's vehicle and is waiting for the order to self-destruct. Seeing an opportunity to finally dispose of one of the Freedom Fighters, Dr. Eggman has the robot latched onto Antoine instead before telling it to detonate. The explosion seemingly kills Antoine, but Sonic hears that he is still breathing. Sonic races with his fallen friend back to New Mobotropolis which saves Antoine's life but is now in a coma.
Post-Super Genesis Wave
A young Antoine first came under service of King Acorn after being sent to Mobotropolis as part of a student exchange program. Taking his father's sword, Antoine pledged his allegiance to the Kingdom of Acorn and swore to protect it's people. However, when Doctor Ivo "Eggman" Robotnik rose to power, Antoine was terrified for his own life and fled from the city.
Although his pride was wounded, Antoine tried to keep up a brave facade by sticking close to Princess Sally Acorn, even though he thought her ideas of leaving the safety of Knothole Village were terrifying. Antoine soon found himself becoming attracted to Sally and tried to impress her, but she didn't return his feelings. Things became worst for Antoine when Sonic the Hedgehog first appeared, his skills and bravery began to make Antoine feel useless as a protector. However, after seeing Bunnie Rabbot trying to gain the use of her Roboticized limbs, Antoine was inspired to try harder and became a member of the Freedom Fighters.
Over time, Antoine's bravery grew and eventually admitted his past cowardliness to Bunnie, who commended Antoine for his continued courage despite his fears, and revealed that he served as an inspiration for her as well. Antoine's friendship with Bunnie soon blossomed into a romance and eventually the two got married. Afterwards, Antoine continues to aid his wife and the other Freedom Fighters in protecting the world from the Eggman Empire.