What things specifically?
From what I've learned, most people like to make themselves from all over the place. I'd say it depends more on the story itself. If the plot deals with us being competitive, against each other, like in a big Tournament - I'd say all over the place. If it deals with being more cooperative, I'd rather be from the same clan so that we can have a pre-established since of friendship or rivalry with each other to begin with. While a few being from other places would be a nice touch in there, I prefer it so we don't have to worry about the relationship building so much to begin with.
Yes the storyline is about cooperation, dealing with external threats and the history of the land. The setting as a whole based on the fact that the nation has been locked in a nation wide civil war for hundreds of years with the various clans still trying to fully take over or carve their own niche. So didn't know if people want it open to deal with hostility towards each other, or all from allied/the same clan.
Yes mostly Japan inspired, so like katanas and kamas etc. But think like some anime or even final fantasy, in that more out there type weapons are an option also. Not only is the world fantasy, but the other nations have much more advanced tech so guns and stuff are an option to richer characters (not as effective as in our world though, do to magic and people being more superhuman)
My original character has the power to manipulate anything and anyone with just her left hand. She can surpass any defense with her right hand. She's been crushed between a thousand nebula all converging upon each other and tore her way out. She knows over five thousand techniques both physical and non. Her armory is so vast that it defies human logic both in quantity and quality. In order to RP her, the term "God-modding" cannot exist. Lol. One of her techniques is a straight attack that CANNOT be stopped or blocked. The only way to not be "insta-killed" by it is pretty much to get out of the way. Despite the clear dodge factor here, it means that no matter what the defense it takes them out which others will easily clarify as "unfair".
Now, for an RP like what you're discussing.. I can probably throw in a few unique weapons custom made and some unique factors. Though based on what it sounds like, no powers.