Born to renowned terraformer Doctor Bernard Hanson and geneticist Talise Cogan, Ariel Hanson grew up on Agria, a colony founded by her father when he and Talise divorced. Ariel showed her genius at an early age; at age six, she began poring over her father's old chemistry digi-tomes. At eleven, she published her first research paper about the effects of mutagenic chemicals on the rare trabillia flower. At sixteen, after graduating from upper school two years ahead of her peers, she received a full scholarship to Tarsonis University, a prestigious institute that was also attended by her father. Despite the rich bio-diversity of Agria and her father's objection, she accepted grant and traveled to Tarsonis.

During the three years on Tarsonis, Hanson earned a bio-engineering doctorate but refrained from accepting a job offer there. Disenfranchised by the crass, ruthless and arrogant intellectuals there – especially her own mother – she returned to Agria. Her mother only proclaimed she was simply running away from the "real" world, just as her father had. The words only reaffirmed Hanson's decision: if Tarsonis was the real world, it was one she didn't want to be a part of.

While her father remained the colony's chairman, she effectively became his second-in-command. Her duties included holding a round of hands-on health examinations. Agria remained largely unscathed by the fall of the Confederacy. The Terran Dominion retained Agria's status and even stationed a permanent defense force there.

In 2503 pirates raided the colony, intending to steal its advanced technology. The Dominion fought back, but many innocent colonists were killed in the crossfire. Hanson risked her life to save dozens of innocent bystanders trapped in areas of heavy fighting. She now believed the Dominion saw the colonists as expendable.

The Second Great War

"...any ship receiving this transmission...the zerg are invading Agria...The Dominion abandoned us here ...We're just a small farming colony. We've got to evacuate before we're overrun....If you can hear this message, please help us!"

- Hanson's distress call.

The Second Great War further intensified Hanson's hatred of the Dominion: When the zerg invaded the planet, the Dominion fleet pulled back to the core worlds instead of defending. Instead, Raynor's Raiders responded to Hanson's distress call and successfully evacuated as many colonists as possible.

The colonists resettled on Meinhoff. Hanson, however, stayed with the Raiders to assist them, as they had neither a modern medical facility nor scientific expertise. As artifact pieces were gathered by Raynor's Raiders, Hanson studied the mysterious device, discovering that protoss could be killed simply being in close proximity to it.

On Meinhoff, a zerg infestation struck the colony, but it was purged by the Raiders. At Raynor's suggestion, she began to devise a cure for the virus.