Plot: 10/10
The beginning of the story sets the stage well, and the build-up from the room, to the house, to the rest of the mansion, and from the children to the power-players are magnificent.
Characters: 10/10
Character interaction between the shadows and their living dolls is the main plot and heavily focused on, so naturally the characters are well-made. also the introducion of characters and building them up in a masterful way.
Drawings: 10/10 (coloured!) (also soot looks great!)
World-building: 10/10
The story is unique, refreshing, but believable. Draws you in nicely. The mansion is awesome, well -explained.
But it's a cutesy manga, doesn't feel like seinen at all. Don't let that deter you though, it's too good to pass up.