Killian's progressing relationship with Hestia de Bayle comes with more than its fair share of problems, and has since before he began to court her - when he was caught kissing her by her one-time fiancé. Though they didn't have it easy in the following moons, as their relationship developed into something more serious, the couple began looking toward the future. Questions of marriage and family arose, and the latter left them wondering if it was even possible to have children. With both of their respective illnesses, neither of them wanted to risk the potential of their children suffering the way they had. And while the cause of Hestia's illness could be pinpointed and dealt with, the pair had no such information on the issues that plagued Killian, nor whether or not they would be passed down onto his offspring. And so, they sought out their one lead that might guide them to answers - however unlikely it might be - Killian's mother.
Killian already had her name - Áine Waltz - but precious little information about her aside from that. Only a chance meeting with his half-sister some moons past gave him any further insight onto who his mother might be or where she was from - the one blessing from the otherwise entirely unpleasant experience that was speaking with his elder sister for the first and only time. All he knew then was that Áine was Ishgardian. Nothing about whether she was noble or lowborn, whether she was married or not, or even if she'd had other children. It wasn't much, but it was something, at least, and that was better than nothing.
Hestia took the first step in inquiring about the woman through House Fortemps. Their search yielded limited results, given the twenty-some years that have passed since Áine's death, but they were given a letter with which they might be granted an audience with the other high houses. Upon reaching House Durendaire, Hestia and Killian were supplied with a wealth of information about the mysterious woman who'd left the Holy See some thirty years past - "or closer to than twenty," as a baron named Cereveaux described to them. "A rather insistent, particularly ambitious young woman," he said, "who managed to claw her way out of the Brume. Somehow." A charismatic, educated woman with a tall ambition, a keen sense for politics, and a love of history and scholarly pursuit with a particular focus on Ishgardian astrology. A woman of milky skin, dusted with freckles, bright blue eyes, fiery hair that draped in curls down past her shoulders and a slender, womanly frame. One that she knew how to use, if Cereveaux's description held any merit - once Áine had climbed the social ladder, she had plenty of suitors to choose from. She was removed from service to House Durendaire after a one-time fling left her pregnant with a bastard child. The last Cereveaux had known, she'd had the child within the city walls and left it at an orphanage to pursue her studies under a new, lesser house - House Garnier - at the Observatorium, presumably where she would focus on astrology.
With promises of delivering whatever he could about Áine to Fortemps so that Killian and Hestia might learn more, the baron bade them goodnight with little else in the way of information. Only some weeks later, well after Guillemont's capture and Aegisan's birth, did those records finally make their way to the now-engaged couple. The information within spoke more to Áine's past: her history of social networking, her ambitious and forward-thinking demeanor, her silver-tongued nature that could get her out of most trouble. Her medical records were scant, as were those of her firstborn, but neither suggested any health issues, leaving Killian only more confused about the origin and nature of his own illnesses.
At a loss, Hestia and Killian - now married - visited the Observatorium in an attempt at finding anyone from House Garnier that might still live in the small settlement. They were fortunate in finding a middle-aged Elezen woman named Olivie Garnier who, apparently, knew Áine personally, but Olivie knew nothing about any lover or even a child of Áine's. According to the woman, Áine left for Mor Dhona some five or ten years after moving to the Observatorium to study Silvertear Lake with a small expedition team. None from the team were heard from again, presumed dead after the Battle of Silvertear Skies decimated much of Mor Dhona's landscape. With the knowledge that other members of the original expedition team might have survived the battle, Olivie promised to send out her own men to seek out information on anyone originally thought dead, offering to pass on what information she might find to Hestia and Killian before sending them on their way.
It was Hestia who chose to explore the lead in Mor Dhona, however thin that thread might be. As such, Killian knows little about the search, except that it took quite some time before she stumbled, quite by happenstance, on one of the men sent by Olivie on his own search - Évariste Garnier. Opting to work together to follow the trail of an old hermit rumored to have survived both the Battle of Silvertear Skies and the Calamity, the pair made their way north to a crystalline cave where the man was said to reside. Their search was rewarded, somewhat, with information, but the crazed Elezen tried to capture them, and Hestia was forced to slay him.
What they learned was of mixed worth. The man was apparently part of the expedition originally sent to Mor Dhona, and supplied them with the knowledge that Áine had been captured some time before the battle by Garlean forces. The timeline of Killian's birth suggests that he must have been sired during her capture, assuming she was in Mor Dhona for the notorious battle there. Aside from that, she was presumed dead; the crazed man had nothing else by way of information as far as Áine's whereabouts.
Évariste was, however, able to find a dilapidated journal, and after several days of careful attempts at copying what could still be read, he personally delivered the information to Hestia. The copy contained more of the same information, but, struck with the hope for more, Hestia turned to the de Bayle librarian, Quarcy Questant, in hopes that the Elezen would be able to restore the old journal. As this discussion progressed, it turned into a plan: infiltrate Castrum Centri in search of pre-Calamity records on Garlean prisoners and personnel. It was this risky mission that yielded the most information, both on Killian's mother...and his father.
His father: Cyrus lux Merulus. One of the chief medical personnel and leader of a team of researchers in the area. After Áine's difficulty recovering from injuries sustained after her capture, Cyrus personally oversaw her recovery and conscription into his team. She became Áine aan Vestoria, and the two shared...some kind of bond. Love, or mutual interest, or something else entirely was left unclear; what they discovered only suggested that Cyrus - a pure-blooded Garlean - was the father, with a clean bill of health...and that Áine was pregnant with not one child, but two. Twins. A sister. Yet with no name to go by - nor even knowledge of whether or not she's alive, or afflicted by the same problems as Killian - there seems to be little hope of finding more information about her. His strongest lead to learning more about his family seems to be in seeking out his father, currently stationed in Castrum Centri...but given the risk that entails, when Killian's initial goal - to find out if it's safe for him to sire a child - has been reached already, makes this endeavor one to ponder long and hard before proceeding.