Cal was born in Vault 76, a Vault-Tec installment in West Virginia dedicated to preserving the lineages of pre-war America's best and brightest minds. Unlike his peers, however, Cal didn't possess genius-level intelligence. Known as "Calamity" by his peers due to his perceived clumsiness, Cal endured regular sneering from the Vault's more privileged residents, many of whom were already being groomed to rebuild America following the annihilation caused by nuclear war. What might have been normal standardized test scores for us were considered wildly sub-par by Vault 76's standards, and Cal was relegated to the janitorial position usually awarded to "failures and imbeciles".
Such was Cal's unpopularity in Vault 76 that he wasn't even informed that the Vault doors would be opening as scheduled, instead waking up to find the other residents had already dispersed into wild Appalachia. As he picked his way through the remnants of the only home he'd ever known, Cal was told that Vault 76's life-support systems would be switched off per established Vault-Tec procedure. He had no choice but to emerge, blinking, into the wasteland.
Cal had received only a fraction of the survival training given to the Vault's more "promising" residents, and he initially struggled to adjust to life outside its confines. He was able to find a nearby settlement, the Wayward, that had been established by post-War survivors migrating into the Appalachia region, and relied on them for shelter in exchange for labour. Cal ate up every scrap of kindness he was given, and soon grew attached to his new friends. When he noticed the Wayward's proprietor, Duchess, was having issues with aggressive treasure-hunters looking for a man called "Crane", Cal was all-too-easily sweet-talked into solving the issue for her.
His investigation eventually led him to the Free Radicals, a group of ex-convicts turned raiders operating under the leadership of the former prison warden, Roper. The journey to the former WV Lumber Co. building had taken a hard toll on Cal's body, and he arrived at the Free Radicals' camp in a poor state. Perhaps sensing that Cal could be easily manipulated by any show of tenderness, Roper allowed his men to render aid as necessary. He subsequently agreed to leave the Wayward alone in return for Cal's help finding Crane's treasure. In reality, Cal was both hostage and informant; Roper had already sent word to the Wayward that he had one of their men, and that he intended on pumping him for information about Crane's whereabouts.
It was during one of his excursions at Roper's behest that Cal discovered the Responders, a volunteer disaster relief organization attempting to re-establish itself in Appalachia. Despite having no medical training of his own, Cal readily agreed to join the cause; he diligently studied the notes left by the survivors of the Great War, in the hopes of being able to make himself of use to his new allies.
Cal eventually stumbled across the Overseer of Vault 76 in Sutton, where she had been attempting to enlist other former Vault residents in helping her secure three nuclear silos for the Vault-Tec corporation. Cal was the only former member of the Vault to have responded to her call, and she was dismayed by the fact that he'd found her more or less accidentally. In the confrontation that followed, the Vault Overseer re-stated her loyalty to Vault 76's mission, and expressing disappointment that it was Cal who had sought her out rather than someone more qualified for the job.
Cal subsequently returned to the Wayward, where he learned that Duchess and had been lying to him all along: the man formerly known as Crane was, in fact, chained up in the Wayward's back room. Since Cal had known nothing about this, Duchess had ignored Roper's demands to negotiate over Cal's well-being. The realization that he had been used by people he had trusted broke something in Cal, and he returned to the WV Lumber Co. to join the Free Radicals for good.
Cal, as he appears in Fallout 76, wearing his signature Responders jumpsuit. Fallout 76 is incompatible with appearance mods; his modded version is probably his "canonical" appearance.
(Fallout 76) The leader of the Free Radicals, Roper is a selectively moral leader who delights in keeping Cal under his thumb. Cal is addicted to the crumbs of affection Roper offers him.
(Fallout 76) Former drug baron and owner of the Wayward. Cal considered Duchess a friend and maternal figure, and was devastated to find that she had been manipulating him all along.
(Fallout 76) A paid-up believer in Vault-Tec's theory of eugenics, the Overseer makes no secret that she considers Cal generally unfit for the prestigious work of rebuilding Appalachia.
A note on Ships: Given his experiences in the Vault, Cal/Roper may actually be Cal's first "serious" relationship. If you're looking for problematic content, you need look no further than Roper, whose willingness to render aid is always underscored by his conniving nature. By the time Cal joins the Free Radicals full-time Roper is the only person in Appalachia who he loves and trusts, and Roper alternately covets and exploits Cal's unwavering loyalty to him.