Antoine was a male Human colonist on Serafin's Planet in the mid 24th century. As such, he had suffered from a debilitating and disfiguring genetic disease, until a seismic event on the planet unearthed a mysterious radiation source. This radiation cured the disease, but left the colonists with the need to feed on the life-force of other living beings.
Antoine was the leader of the eight colonists who survived the destruction of the planet by seismic forces. He warned Miguel Uribe and Dahlia Santorini to avoid personal entanglements while aboard the USS Enterprise-D, telling them it was to great a risk and temptation to reveal to them what had happened on Serafin's Planet. (TNG comics: "Serafin's Survivors", "Shadows in the Garden")