I don't know why, but, I always see Poniko as a bitch character in either a drama or comedy or dramedy series. Although, not the real bitch, just the main bitch. If that makes sense. Although, from a non-comedy/dramedy way, probably either quiet or even introverted. Or maybe shy.
poniko is a screamo singer
I just wanted to point out how it's kind of funny that you say they are childhood friends, but in the picture, Madotsuki is holding a knife while glaring at her.
I found that amusing myself.
Who knows, Poniko could of been a complete bitch. A bully, a monster, who knows? I'm just more fond of the more positive theory, personally.
I see Poniko as Mado's childhood friend who suffered/s from Multiple Personality disorder and this personality (represented by Uboa) ruined part of Mado's childhood (maybe she had a birthday party and he messed it up or something, which would explain the balloons leading up to Poniko's islandy thing)
I think Poniko would be the opposite of Madotsuki. Their rooms and colourschemes seem to be opposite or similar. I think she'd be outgoing, and more social and easygoing.
Uboa…I've grown to love him so he just looks adorable to me now after all the fanart. He just had a dopey smile. I think of him as a slow, dimwitted or possibly mentally retarded ghost who likes to dance and sing AH TAN NEET CENTIMETER.
Maybe it's like 50 First Dates and he keeps forgetting that he already sang and danced and so he KEEPS DOING IT OVER AND OVER AGAIN.
I see Poniko as a large-breasted blonde.
And Ubuu is a frozen semen blob painted with black paint.
Give me that.
I want THAT NOW.
I see Poniko as a mute who more or less didn't mind Madotsuki very much. But then Uboa is a representation of Poniko's frustration who, after being annoyed enough, started being mean to Madotsuki. She pushed her around, hit her, etc. Because of the sudden dramatic change of attitude, it stuck in Madotsuki's mind as an extreme change in how she saw Poniko.