[Birth]Castiel Pace is the eldest twin son of Answald Pace and Minamoto no Utahime (rendered as 'Utahime Minamoto' in Eorzea standard), born of an illicit relationship between his Ala Mhigan father and Doman mother. Inheriting more of the latter's Midlander attributes, his Doman name is Mitsurugi. His father came from humble beginnings, once serving as a courier for the fortress city before being conscripted as a warrior during the late King Theodoric's lunacy-driven genocide against the Fist of Rhalgr.
His mother was the esteemed princess of the prestigious Minamoto clan, whose history and lineage are directly tied to the royal family of Doma, having served as their very first retainers. Trained as a shinobi from a very young age, Utahime fled her home country to warn the western world of the Garlean invasion, and met Answald when her ship crashed on the Velodyna River near Ala Mhigo. Her admonition would fall on deaf ears after learning of the status quo, opting to help Answald with the resistance effort.
Born three years before the Garlean invasion of Ala Mhigo alongside his younger twin sister, Castella, Castiel has but a faint recollection of his father and turbulent time period, most of his impressions coming secondhand from his mother's account. Believing his father to have perished during the seizure of the fortress city, the two were among the staggering flocks of refugees migrating into Eorzea; a majority of them had been refused entry into Gridania by the Elementals of the Black Shroud, though the young boy and his mother were allowed into the city-state with impunity.
[Adolescence]Castiel and his small family would reside in relative peace within the city-state shrouded in forest, where his mother found a modest livelihood with the Trapper's League and the Leatherworker's Guild. While Utahime attempted to instill the teachings of the shinobi with the twin siblings, only his sister showed a means of reciprocating potential, as the young boy had been far more prone to rowdy behavior compared to the disciplined Castella. Instead, he showed interest in the handling of swords and multitude of other armaments, to which his mother compared her son's likeness to his late father. His adept learning of the disciplines was noticed even by the Wood Wailers, who oftentimes found themselves bested in sparring matches to their embarrassment by the teenager.
The young boy was always surrounded by many friends alike, mostly acquainting himself with the orphaned Gridanian children. Castiel would find a truer confidant in another boy named Noceo, whom he had originally mocked throughout the years until a scolding from Utahime set him straight. Despite his mother's frequent interjection with the boy's behavior, he maintained a jarring reputation within Gridania as a mischief-maker alongside his posse, often spelling trouble for the Wood Wailers and the rightful elderfolk with their actions; on the fateful days and nights leading towards the catastrophic event that would forever scar Eorzea, the Calamity would be no different for the eighteen year old.
On the night of moonfall, Castiel wanted a closer view of Dalamud, continually pressing the reserved Noceo to accompany him. The plan involved riding a pair of 'borrowed' chocobos from the stables near the Carline Canopy, and ride past the Yellow Serpent Gate into the North Shroud. Noceo protested, stating that it would be too difficult to slip past due to the enacted martial law, but would eventually cave into peer pressure. With many of the locals and Wood Wailers' attention diverted to the sky, the boys were successful in smuggling themselves into the North Shroud.
Making their way towards the overlook of the Alder Springs, Noceo continued to press his best friend of his insecurities, his pleas to return home rebutted by Castiel, who would assure the boy that this sight was to die for. As they were perched in their location of observation, the pair would look on as Dalamud came apart, and the Elder Primal Bahamut sprung from its shell.
A sense of foreboding crept along Castiel's being as he watched ripples of destruction emanate from the supernatural being, while a once-meek Noceo pondered the flares with excitement. As the colossal being tore through the skies and unleashed its rancor all across Eorzea, the boy would find himself shackled with fear as the beast flew across the Black Shroud, raining explosions across the landscape.
When Castiel advised Noceo that it was time to leave, the latter refused, suggesting that he was no longer a coward. The endless fire from Bahamut's Gigaflare crumbled the earth below the two boys, sending Noceo over the edge and hanging helplessly from the faltering cliffside. With the land prepared to cave in and their chocobos mirroring the boys' panic, Noceo called for Castiel to save him. At the height of the moment, Castiel could only regard the situation with overwhelming fear, tormented by the cries and screams of Noceo falling into the abyss as he left his friend behind.
Without turning back, the boy rode the chocobo in his panicked state, finding himself unable to return home and face his mother and the people of Gridania after leaving Noceo to die due to his actions. Castiel wandered without any knowledge of a destination, riding southward for the entire night. He would travel so far that he eventually reached Southern Thanalan, where the boy collapsed alongside his chocobo at the worn entrance of Little Ala Mhigo.
[Adulthood to Present]The eighteen year old had been found and taken into the care of the Ala Mhigan refugees residing in the makeshift camp, and after much conversation, Castiel set off for Ul'dah in search of a sustainable fortune. Upon being inspected and searched at the Gate of Thal, one of the gatekeepers recognized the particular barding of the boy's chocobo, recognizing it to be one of the Monertarist's mounts.
The city watch would throw Castiel into a prison cell, charged with theft and sentenced to several years behind bars. As he lamented on the sudden twist that his life had taken, an opportunity of escape would arise as, several weeks after his arrest, the boy was offered freedom in the form of a coliseum victory. As a Noxius, he would duel one of the champions of the coliseum in an upcoming tournament against a Roegadyn, and if he proved to be the victor, he would walk free. Without a question, he accepted these conditions.
Castiel was only given a handful of days to reacquaint his sword arm before he was pitted against the Roe, an axe-toting brute who was known by the people of Ul'dah as the Butcher of the Bloodsands. With sword and shield, the boy could only put so much of his training into practice as he found himself hard pressed by the Butcher's relentlessness. Only his fleet footwork kept Castiel alive, and he had been on the run from his opponent for the entire duel.
Seeing the Roegadyn's lack of awareness, Castiel would throw his shield haplessly towards his opponent, encapsulating on the vulnerability when the Butcher battered the shield away with his axe. The boy charged the distracted brute with his sword in both hands, driving the blade through his heart and felling the feared Butcher of the Ruby Road. While Castiel was initially worried of the consequences in killing his opponent, the Hypogeum roared in excitement over the climax of the duel, and he was informed of the coliseum's risks that death was an ordinary factor on the Bloodsands.
It would take several months of fighting as a Noxius for Castiel to eventually buy his freedom from the coliseum earnings, during which the people of Ul'dah began to dub him as the Phantom Pace for his agility. Since then, Castiel has made enough of a fortune to own a small lot to himself in the Goblet with employment through the Gladiator's Guild.