Ambrosius Reynard (yes, that's his name, really) "Sandwich" Keller is an example of one of those people whose mere existence is a product of a series of coincidences.
Family:
Father - Girard Keller, Half-Aquarian, half-Virgan artist and occasional critic, met his future wife-to-be between trips back to Aquaria for the Kyros Summerfest (he's a hippie, yo)
Mother - Imogen Elias, Technically Virgon by Colonial citizenship but she's from Hibernia and somehow got shacked up with Girard.
Sisters - Haven't come up with their names yet, sorry. One younger than Amb, one older. He's the middle child.
Ex-Wife - Melissa Afshar, computer engineer and a bit of a misfit in her own family. They divorced due to lifestyle differences but are on friendly and quite pleasant terms. She has custody of their son but Ambrosius has quite open visitation when on leave.
Son - Alexander - He's just a kid, yo. He does kid-like things. His parents think he's badass though. Don't they always? Too bad he has a genetic disease known as "Planter's Syndrome" which requires expensive therapy to keep at bay so he can walk - otherwise he suffers from a screwed-up immune system and a simple allergic attack or common cold can land him in the hospital or worse.
Childhood:
The particulars of the Keller/Elias marriage were amusing and sometimes Ambrosius will tell stories about his family for comic effect, whether his pie-in-the-sky hippie audiovisual artist father or loud "Moon trash" mother got along or had some ridiculous fight over something silly. He may refer to the Celtans of Hibernia as "moon trash" here and there in a self-deprecating manner but is largely fond of them despite their (in his view) occasionally agitating excesses. They're not really causing problems like the separatists of Saggitaron. At least, not for a FEW centuries. He had a bilingual upbringing due to his home situation but it was largely a happy childhood; while he and his parents often felt like they were from completely different worlds they more or less let him do his own thing. He had an overactive imagination as a child and was fed a steady diet of literature by his folks as well as exposure to "classic" (heh heh) film, etc. Of course, he wanted to be a writer. Or a film director. Or whatever creative outlet struck him. Later on in adolescence he gravitated towards technology but still applied his creative eye. While demonstrating an aptitude for computers, he always viewed them as a tool or means to an end. As the Cylon War ended over a decade before he was a born and he had little exposure to military service in his family, he found recent history and the drama surrounding it pretty fascinating. He was maybe a little naive about the "human drama" surrounding it, but that is understandable.
Schooling:
As his family had a traveling lifestyle across several worlds, the young Mr. Keller attended several schools run by the The Ordained Sisters of Many Faces, a certifiably unliked-on-Gemenon theological order of a rather progressive and scholastic religious bent advocating the veneration of the Lords of Kobol with a variety of aspects and names all being applied to the same gods (they DO believe in the Gods, this must be emphasized) but do not take much of scripture literally. That doesn't mean they don't study scripture, they just apply layers of academic abstraction to it all. Keller's extremely proud that he has travelled enough to see eight of the Twelve Colonies with his own eyes and probably used this sophistication to pick up girls at one point or another in the past. While somewhat abandoning his dreams of becoming a screenwriter at a certain point, his options started to whittle down a bit as his family hit some economic hard times and he faced a question of purpose and a crisis of identity in his young adulthood. So, a sort of meandering Literature/Computer Science University of Virgon at Boskirk double-major transitioned into ROTC, into a one-way trip to the Colonial Fleet Academy at Virgon for all the reasons mentioned above. Those and a healthy dose of boredom - for the first time in his life, he felt something really challenging. Military service. Nobody who knew him previously in their wildest dreams would have imagine him going the direction he did — but he did. It even appeared to be a career to him. That's not to say that he doesn't have his internal doubts here and there, but it's not like he's going to rely on submitting ambitious-if-flawed screenplays that the film industry doesn't want.
Academy life/Military Service:
As an adult, Ambrosius Keller scored high marks for reactive and analytical thinking as well as problem-solving. While he was driven enough to make it into flight school he initially wanted to go for the glamorous, competitive vocation of Viper flying. It was the high competition, natural aptitude/inclination or a combination of both that forced him in a different direction, that of an eventually accomplished ECO. He knows how to MOVE an airframe in case of emergency like anyone attending flight school, sure, but it's by no means what he's good at and experienced with. As time passed, he graduated from the Academy with high (if not the highest) honors and was shuttled off to his first tour of duty as an Ensign - CFAB Parizad on Saggitaron, an undesirable posting to say the least. These years were softened somewhat by the meeting of his future wife, Melissa, a Saggitaron engineering major who wasn't keen on her home and more than happy to follow him off that rock two years later where they got married, had a kid, and he ended up at CFAB Radix back "home" on Virgon with new family in tow and a successful review leading to promotion to LTJG. A couple years of a basically happy marriage passed with a dedicated service record (aside from developing a reputation as an occasionally obnoxious prankster - most of that shit was PURE ALLEGATION AND NEVER PROVEN) and another promotion to full LT. aboard The Battlestar Erinys (BS-585) for his first space duty.
Unfortunately this spelled the beginning of the end of his marriage as he discovered his son was sick with a chronic disease that required extensive care and neither he nor his wife handled relations with each other well even though they both bent over backwards to care for their son. It didn't help matters that this came up while he was /away/ on duty, an old story told over and over again throughout the walks of military life. This opened a rift that was never fully healed — although as divorces go, the one that followed was pretty amicable. They're actually still close friends, and family and friends of the couple are secretly hedging bets on when/if the two will get back together.
One other thing to be mentioned regarding the Erinys, it was on this ship that Lt. Keller met his new love. No, I'm not talking about a stripper on shoreleave. I'm talking about the titanium girl with the boom in the trunk - the Colonial Predator attack craft. Faster than a Raptor and designed for one thing, surgical strikes on defended targets, his performance in wargames gave him a new chance to shine as he hadn't actually touched one of these craft since flight school and he worked hard to become an "expert" on their systems as a way to kill time. Even if they're needed in this modern peacetime era. and As this tour was up, he found himself once again wondering what he was going to do with his life. Being recommended for and volunteering for a tour on the good ol' Battlestar Orion suddenly became not a bad idea. Plus - the pay bonus would allow him to not go broke paying for medical treatment for his kid. Of course, this point would soon become moot as we flash-forward to the present day when Lt. Keller embarks on his transfer to his new duty and home for the forseeable future. Life's a bitch, isn't it?