Of course, being a large multiworld organization, there's no doubt that there's a lot of species and ethnicity mix within soldiers, this concept explains of what species and/or ethnicity would dominate a soldier class. Please do note however, that because an ethnicity or species is dominant, it doesn't mean that the other ethnicities cannot be within those lines.
It is worthy to note that in the Navy, the Kappa are a lot more common, as well as Nordic, Celtic, English, Hispanic, and Canadian ethnicities. A Cuban ethnicity is also within the Navy and the least common in the Army.
Preservers often operate among the lines of KGB and the FBI, (As in they operate similarly), which is often no surprise that Preservers are Russian and American. Though there are also some parts that are also some English and Australian points within, as well as Hispanic. The Preserver doesn't have much of a fixed ethnicity, as well as for species. Though the majority of the species is human. It is known that Tengu, smaller Oni, and Demons can also be Preservers.
Being the close-quarters counterpart of Preservers, this doesn't mean that like Preservers, they're kinda Russian and American. Instead, Fencers are often English, Australian, French, and Hispanic. Fencers however, do not have much of a fixed species, like the Preserver class. Fencers can also be Eastern Asian as well as Mongolian. They can also be Turkish.
Tanks are bulky, Tanks are tough, Tanks are giant, Tanks are strong. The Tank class is very, very often, Italian, Celtic (Irish & Scottish), and Russian when it comes to coming about the Humans, however, Oni are also known to have join the ranks of Tanks, Oni Tanks are often considered more dangerous due to their hysterical and extreme strength. Though they often drink on the job as well.
Rats are often considered to be French, Belgian, and of other lines of Slavic, kind of seemingly similar to Belarus' inhabitants. It is also known, however, that Rats have lost a degree of their humanity, and are demonically touched. So it would be more safe to assume that they're of another species, which would be called Fel Human. Therefore Rats aren't human at all.
Jesters are often American and English, as well as Chinese and Japanese in their ethnicity. Given Jesters' fondness of computer science and technology, as well as databasing, it would be no surprise that they would also use leetspeak, and may even use computer voices to mask their voice. Jesters are almost always human, though there are some AIs that can also serve as Jesters.
Dragonologists are very often of eastern Asian descent and ethnicity, though there is also some cases of Southern American as well, due to Dragonologists being of mixed martial arts. While Dragonologists may seem rather human at most, their training drives them to the limit other than conventional use of weapons or needing physical brute strength alone. Therefore effectively making Dragonologists more of superhuman, Dragonologists can also be Oni, as well.
Magistrates are perhaps the most debatable and confusing of all the soldiers in the Trinitarian army, and can be a wide range of ethnicity as well as a wide range of species.. Magistrates are best to be assumed to have no specific ethnicity or species domination assigned to them compared to most. All that is best known is that you'll rarely ever see an Oni Magistrate.
Much like the Magistrate, this class is also the most debatable and confusing, mainly due to the fact that they're hand picked by the Field Lead Omega.
Have only a few species which is all canine and no ethnicity due to them only being able to communicate by barking, whining, as well as a few others means of communication.
The field of Medicine and Doctorates is often far and wide, with many people aspiring to be such. However it has been explained that the Apothecaries are dominantly African, Arabic, Indian, Native American, Canadian, and Southern American. Humans however aren't the only species, and in-fact, Succubi and Incubi are also capable of being such, as well as Psionics.
Field Jesters, as they're more commonly referred to, are often German, Slavic, Nordic, Japanese, and Chinese. Jokers' accents are often not noticeable or not as strong, most likely having to speak more of clear English in order voice recognition to take place, as well as to be understandable. While Jokers are often thought to be human, a notable surprising factor is that Jokers can also be Kappa, who often associate themselves with a Tengu partner.