@KatherinWinterSome information you can gather from backstories;
For the moment at least Griffin, Rost, and Argus seem to be the highest ranked agents in play.
Rost theoretically holds the highest rank of those three as he is both a field agent with seniority holds a special title as the head of research and development.
Griffin is the most senior agent but holds no known special titles; he is a representative of the vampiric court but that does not seem to hold any specific weight within BOSA other than his presence as an agent being a deterrent of open conflict between the two groups.
Overall I would give Rost and Griffin a tie in term of chain of command with who is considered the most senior agent depending purely on context.
Argus has the roughly same level of seniority as Rost but falls at the bottom of the totem pole for senior agents because he was on working probation for the agency until recently.
I can't pin down when precisely Richard joined but he doesn't seem to be brand new; of the newer agents he is most likely the highest in seniority but has not been with the agency long enough to be trusted as the lead for more complex cases just yet. His prior military experience would make him a candidate for early promotion once he has undergone field evaluation by a more senior agent.
Amaya and Mason are both brand new additions to the agency and thus hold no seniority; they are rookie agents still within what you could call a trial period. They have no prior military or police experience and do not have many skills which would qualify them for specialist titles.
Basically, they're interns.
Astra is a special case as far as seniority goes; though she has only just been activated she was reprogrammed to be loyal to the agency and possesses skills and abilities that could easily earn her a specialist rank to bump her further up the ladder than those with comparable time served.
Digi's characters are new to BOSA but do have prior experience with a comparable organization. Under most circumstances this would put them in the same boat as Richard, but since they have ties to an active organization with which BOSA does not have a treaty or alliance they would likely be placed under the supervision of a trusted individual within the agency to determine whether they are spies or legitimate allies.
By the way I read WAY more military fiction than I probably should.
