Hanafuda Koi-koi
There'd be 48 people (I imagine feudal Japan-ish?), one for each card and four born in each month of the year. They're probably a bunch of...well...wandering swordsmen/women? A pretty large group, but yeah.
January:
2 x plain cards, poetry ribbon, Matsu ni Tsuru
February:
2 x plains, poetry ribbon, Ume ni Uguisu
March:
2 x plains, poetry ribbon, Sakura ni Maku
April:
2 x plains, red ribbon, Fuji ni Hototogisu
May:
2 x plains, red ribbon, Sekku to Ayame
June:
2 x plains, blue ribbon, Botan to Chou
July:
2 x plains, red ribbon, Hagi to Inoshishi
August:
2 x plains, birds?, Susuki ni Tsuki
September:
2 x plains, blue ribbon, Kiku to Sakazuki
October:
2 x plains, blue ribbon, Momiji to Shika
November:
1 x plain, red ribbon, bird?, Yanagi ni Ono no Doufuu
December:
3 x plains, Kiri ni Houou
Depending on the rules you play (I'm following the free app I have for the iPhone, and also using this for reference):
The plains are all kids. 10 of them together makes Kasu (trash...) but hey, that's still better than nothing. November's kid is a bit left out, but that's okay, there's one extra for December too.
Kiku to Sakazuki is an all-round popular guy - gets along with Sakura ni Maku (Hanamisake) and Susuki ni Tsuki (Tsukimisake). Plus the kids like him enough to count him in, so he can be considered part of the Kasu group too.
The animal cards have their own band too - Ume ni Uguisu, Fuji ni Hototogisu, Sekku to Ayame (didn't have anywhere to go, so they took him/her in), Botan to Chou, Hagi to Inoshishi, Momiji to Shika, the two birds, and whaddya know apparently Kiku to Sakazuki also counts as an animal card. Five of them can form Tane.
Hagi to Inoshishi, Momiji to Shika, Botan to Chou are a pretty close trio, making Ino-Shika-Chou. They're pretty powerful, at 5 points.
The three poetry ribbons (Akatan) and three blue ribbons (Aotan) are slightly stronger at 6 points each. Maybe triplets, or something. Five of any ribbon (Tanzaku) is, well, pretty weak (I guess their fighting styles don't coordinate or something?) at 1 point.
Three of Sakura ni Maku, Matsu ni Tsuru, Susuki ni Tsuki, and Kiri ni Houou make the yaku of Sankou, about as strong at the Akatan/Aotan trios. If Yanagi ni Ono no Doufuu is present, then that's 8 points (Ame-Shikou); otherwise if the missing one of the original four named above is present, then that's 10 points (Shikou). If all five are present (Gokou) it's 15 points, the strongest group of the lot.
I'm not too sure about their personalities or whatnot, but I think-
- Sakura ni Maku is a pretty sweet girl who would probably be the canon female love interest of Kiku ni Sakazuki
- Kiku to Sakazuki is quite the playboy (nice guy who's always drinking but somehow is never drunk)
- Kiri ni Houou is the serious oneesan type
- the single willow plain card is a quiet kid who's talented but isn't comfortable with people
- Hagi to Inoshishi is a big guy with a paunch and the strength of a...well..boar, and is generally nice
- Botan to Chou is a girl who's a little immature, likes to whine, but she does have her strengths
- Susuki ni Tsuki is Kiku to Sakazuki's best friend, a reserved guy who appreciates Kiku's company, such that fangirls ship both of them very hard.
- Yanagi ni Ono no Doufuu somehow manages to end up soaking wet a lot of the time. People blame him for bringing rain (jokingly).
- Matsu ni Tsuru would be that swordsman in white who takes it upon himself to protect everyone else. He's supposedly very old but no one's verified that, and anyway he looks only about 20.