Rena - Always going to be my favorite one, still she didnt have too much screentime, still is Rena were talking about, omochikaeri, hauu~, well you know what Im talking about.
Keiichi - Really awesome, the first time, I cheered for him even knowing at first he was a scared guy and never did anything but cry, and in 2nd season he didnt let me down xD awesome character, Go K.
Shion - Always surprising me the first time something seemed fishy about her and always beeing that lovely, then she goes insane, in season 2 the relation she has with satoko is awesome plus that scene with satoshi (Ah and dont forget she can handle weapons xD) for me she seems like a winner :P
Rika & Hanyuu - Very interesting character enduring all that pain just to see everyone alive and happy, we all love rika what could we say T.T, and hanyuu well, hanyuu is hanyuu its all i have to say
Takano - Never expected her to be that awesome
really awesome character.
Akasaka & Kasai - Kickass, very cool scenes akasaka fighting and kasai handling weapons
I love all the characters but posting something avout every character would be annoying.