So, if one were, hypothetically, to write some Prince of Tennis fic, then one would need to puzzle out the intricacies of who calls whom by what name when and with what honorific. I'm up to speed enough for watching. I've googled a lot and most sites have the same basic info, which is good enough to get an idea of what's going on. But composition requires more knowledge than simple comprehension and that's where I'm having trouble.
For example, among the third years (by each other, that is, not by outsiders), some are addressed only by their family names without an honorific -- Fuji, Oishi. Eiji goes by his given name, also without an honorific. Kawamura is often called Taka-san, a shortened form of his given name with -san added. Why is it so different among them? When can you use someone's given name?
Here are three different sets of characters. Assuming that what they call each other in canon reflects a friendly relationship, how would it change if they were A. close friends or B. romantically involved? If you don't know the show but want to take a stab anyhow, I'll put in some info about the characters. All names written with family name first, then given name. These are boys, not men, at school. And these aren't necessarily who I plan to write about, but I thought they'd make good examples.
1. Echizen Ryoma -- first year student, loner, somewhat bratty and not terribly deferential. (From spending his formative years in America?) Calls Momoshiro "Momo-senpai".
Momoshiro Takeshi -- second year student, outgoing, laid back, caused first year students to nearly faint by insisting they call him "Momo-chan". (They were just barely able to manage "Momo-chan-senpai".) Calls Echizen "Echizen".
Echizen and Momoshiro pal around after school a lot.
2. Kaidoh Kaoru -- second year, loner, serious, irritable, but respectful and observing of proprieties. Calls Inui "senpai" when he addresses him at all.
Inui Sadaharu -- third year, serious, smart, somewhat evil. Calls Kaidoh "Kaidoh", which he does quite a lot.
Inui and Kaidoh are in love not exactly friendly but they train together and have a somewhat complex unspoken relationship. In my opinion.
3. Fuji Syusuke -- third year, smiling, friendly, very evil. Calls Kawamura "Taka-san", I think. (I confess, I'm not quite sure -- but it's what most of the third years seem to call him.)
Kawamura Takashi -- third year, friendly, almost shy except when playing tennis, when he pretty much goes berserk. Calls Fuji "Fuji".
They play doubles sometimes and are generally friendly with each other.
I would be ever so grateful to anyone who could help me out with this. I really don't want to mess this up and look stupid.