Not to be confused with Western playing cards (which have four suits of 13 cards each), Japanese playing cards have 12 suits with four cards each. Each suit represents a different month of the year, a different flower, and a different Special(s). In this case, they each also sport a different Durarara!! mascot. wiki source.
January - Pine - Crane & Sun - Akabayashi
February - Plum Blossom - Bush-warbler - Shinra
March - Cherry Blossom - Camp Curtain - Akane
April - Wisteria - Cuckoo - Celty
May - Iris - Water Iris - Dotachinn
June - Peony - Butterflies - Anri
July - Bush Clover - Boar - Kida
August - Susuki Grass - Full moon with red sky - Izaya
September - Chrysanthemum - Poetry sake cup - Shizuo
October - Maple - Deer - Mikado
November - Willow - Lightning/Swallow/Rainman with umbrella and frog - Simon
December - Paulownia - Chinese Phoenix - Shiki
eh bet yu aher ehwl glehd tu seh meh in sehsen tuu..
There’s really not enough Tom Tanaka in the world, I think. Here are a few pics of me cosplaying him.