Rokugan.
I wrote a 5e conversion of this setting, it's somewhere buried in ENWorld forums if you can find it.
[MENTION=6775477]Shiroiken[/MENTION] has already mentioned many of its features, but I'll toss a few words of my own here as well.
[*]What made you choose this setting
The setting is based on the L5R card game, but I have never actually played it. It also had its own RPG, but I haven't played that either. I started from the 3e Oriental Adventures which featured Rokugan as default setting, but in practice the OA book had a lot of additional stuff which was
not part of Rokugan. But for some reasons, even if Rokugan was a small subset of the OA material, it stroke me as having a strong identity of its own. OA as a whole felt like vanilla D&D with an oriental flavor, but if you only took Rokugan, then it was a lot more distinctive. Sometimes, restrictions and limitations end up in stronger character and identity!
[*]How it's different from standard D&D settings
In
a lot of ways! You have to throw away many typical D&D starting assumption, most importantly these 4:
- D&D typically assumes a world with lots of humanoid races, with the PCs being a mix of them > In Rokugan, all PCs are normally humans. But not all humans, only noble samurai or bushi (the majority of people doesn't make for playable characters).
- D&D assumes a modern ethic: the distinction between good and evil is important, even if characters fall in between. You also assume that for example theft and murder are crimes and will be prosecuted, and the potential victims have the rights to defend themselves. > In Rokugan, everyone else than nobles are below. Things work very differently... there isn't much concern between straightforward Good and Evil, only between Honorable and Dishonorable.
- D&D assumes a modern economy: your PCs earn money and spend it on useful equipment > In Rokugan, money is pointless for the PCs, because they are all provided for by their clans. There is no private property, there is only clan property, and technically not even that because everything belongs to the Emperor.
- D&D assumes knowledge and skills are largely available: if you want to learn something, you just do > In Rokugan, all knowledge (practical or not) comes strictly from master-students relations. You don't learn something by yourself. You don't cherrypick knowledge in the same unlimited way as in standard D&D. Because knowledge is jealously guarded, so you just can't decide that your PC will learn something that is taught by another clan or school.
[*]The types of PCs and adventures that make sense for this setting
There is a much larger focus on intrigue, social interaction and mistery. Combat happens more rarely, and it's often short and deadly. Treasure hunting is practically non-existent. Most quests are triggered by superior orders, not PC's own initiative.
[*]Changes in fluff or crunch to accommodate this setting
Classes are totally different, essentially Samurai (warrior), Shugenja (spellcaster), Courtier (skilled) and Monk. These are big roles in the world, and you don't mix them up (except Monk that can work a bit like a dual class). In my 5e conversion I have only these 4 classes, however you
can technically feature other classes and allow multiclassing, but you have to keep it a matter of behind-the-curtains choice,
not a matter of character concept. In other words, characters could
technically be e.g Samurai/Fighter/Ranger but
conceptually they are either Samurai, Shugenja or Courtier, each one is a different pillar in the order of the universe, and nobody belongs to more than one.
Reputation is very important, and skills contribute to that. Almost everyone should have some skills in something artistic. Many practical skills are instead considered dishonorable if practiced by a noble. In addition, excellence is important, so it usually isn't a case of a character "dabbling" in a skill: you either pursue excellence or you don't do it at all. These require some adjustments in how you hand out skill proficiencies to characters, e.g. it makes sense in 5e that everyone has access to Expertise.
Standard Backgrounds don't work. Almost none of them make sense for a samurai, and their downtime benefits are not applicable. I don't think you want everyone to have the same Noble background. In my 5e conversion, I have replaced standard backgrounds with backgrounds that represent the
family.
It may not be strictly mandatory, but you should probably use some additional rules modules for tracking
Honor and for handling the
Taint. But I guess you could also choose to manage both at a purely narrative level.
