DreaMarbleng (ドリーマーブリング)/theories

Dark side of Irotsuki
Even though seems like a harmless dreamer, Irotsuki has a dark side. But this evil personality is hidden among chasers and also known as True Failed Maker. There are two Failed Makers, and although they have the same shades of colors, they're different and one of them have no eyes and have something like a bloody stain or spot on a face, and this is the True Failed Maker aka Senshoku. But in compare of her failed clones, Senshoku doesn't attack Iro-chan personally and tries ruining Iro's dream instead. Judging by her actions that she actually kills some dream monsters like NPCs, she can reflect Iro-chan's hidden disgust at her arts, meaning Irotsuki have been so uncertain about her own skills that these negative feelings flowed in that special chaser. Also since one of chasers is copy of Iro' lil sister but in negative, that meaning Senshoku and her failed clones are bad drawn copies of Iro, her other selves.

Parents of Irotsuki
Doctor Dandy and DS-QM can be father and mother of Irotsuki and Riyu (little sister of Iro-chan). This can be proved by fact that Doc D and DS have almost same color of hair like of Iro. Probably the situation is, Iro's mother has been very sick and Iro often bought a medicine for her, meanwhile Dandy was a scientist and have been so busy that couldn't take a time to care DS and their children, in the end DS is gone from her sickness. After that, Dandy seems to became distant for his kids and fully dig in his work, but probably in ending with a letter (possibly written by Dandy), where he is apologizing for that he was a bad father and that he will return soon to care about his kids, but question is that can Irotsuki forgive him.