Dream Hunter Rem XX: The Blue Mechanical Knight

Unbeknownst to her, young detective Reimu finds herself trapped in a dream world.
While speeding through the dreamlike galaxy on a train, she witnesses
girls being violated by tentacles, their bodies covered in blue flesh.

Meanwhile, in the real world, a series of girl disappearances occur, and
Sakaki, sensing the involvement of a supernatural entity, secretly begins an investigation.

After a fierce battle with a mysterious villain, Reimu returns to the real world.
However, the girls are taken hostage, and she is captured and
subjected to a brutal physical examination, her body violated from her womb to her anus.

Who is the succubus lurking in the shadows of this incident?!