The artist missed a lot of the blue haired characters if that's what he/she was going for.

Engrishname said:

The artist missed a lot of the blue haired characters if that's what he/she was going for.

Who else other than Seiga, Remilia, Keine, Kanako, Tenshi, Iku, Cirno, & Wakasagihime is blue-haired? Outside of the group in the image I mean.

Engrishname said:

The artist missed a lot of the blue haired characters if that's what he/she was going for.

Who, besides these four characters, are dressed in all blue? I think that's what the artist played on.

makosful said:

Who, besides these four characters, are dressed in all blue? I think that's what the artist played on.

Cirno and Seiga?

According to the artist's comments those are the girls she likes to draw a lot more often than even her favorite Touhou characters, and they all happen to be blue.