Majin Devil

The creature standing on top of the evolution system isn't human, but a creature named The Majin. Majin Devil is a story about a young nerd who fights against monsters of all sorts, and eventually faces Majin, who wants to take his body.

Majin Devil is a 2001 2-book manga series by Oh Great! (Ogure Ito). With that, comes Oh Great!'s infamous "story-telling" (he comes up with his own rules for defying physics, biology, etc). Some people may need Brain Bleach after reading this.

This manga provides examples of:
 * A Friend in Need: Haru is Tomoe's old friend from middle school Guess who comes to Tomoe's aid when she was chased by other rokuro-kubi human-turned-devils?
 * Aerith and Bob: Kazuya, Tetsu, Satomi, Tomoe, and... Harry?
 * Asskicking Pose: Dekoppa, a few times. Sometimes with Stuff Blowing Up (or otherwise disintegrating) on the background.
 * Ass Shove: Hayashi-sensei did this on Harry... with a lit cigarette.
 * Backstory: The first two chapters.
 * Badass: If this series runs on nightmare, then badass is the motor oil. Tetsu and Satomi are the plain examples.
 * Badass Bookworm: Dekoppa when not possessed. "After all, I am the son of a biologist."
 * Badass Normal: Dekoppa, who curbstomps legitimate monsters... with science!
 * Battle in the Center of the Mind: in the final chapter. See also CMoA below.
 * BFG: The Majin had one on his arm as his main mode of asshanding.
 * Body Horror: Too many to list, but one of the worst is chapter 3. The guy also sleeps with women and impregnates them with embryo/spider monsters that either burst out of the woman's womb or emerge from her belly, like the Chest Burster in Aliens.
 * Oh, and the, described in loving detail (with live practice!) by the resident Mad Scientist.
 * Curb Stomp Battle: Well, the titular Majin/Pale Vampire is the embodiment of this. That is, until
 * Did Not Do Research: Somewhere, a biologist, physicist, mathematician, and biochemist are crying together.
 * Lampshaded by Tomoe when she was chased by a gang of rokuro-kubi.
 * Embarrassing Nickname: The protaganist is nicknamed Dekoppa. His real name is Idetora Kazuya.
 * The End - or Is It?: In the ending,
 * Even Bad Men Love Their Mamas: The Fuuga Clan chief/sole survivor in Chapter 6.
 * Eye Scream: The making of rokuro-kubi devils.
 * For Science!: The Professor. He likes to study things, and it's no surprise that things get out of hand later on... on the other hand, Hayashi-sensei is this on a much lesser degree. Dekoppa's parents is a questionable case, since they are researchers but it isn't clear whether For Science! is the reason for the Parental Abandonment.
 * Grand Theft Me:
 * Hannibal Lecture: The Professor delivers one in chapter 6. Dekoppa's in the final chapter can be considered as this.
 * Hit Points: Dekoppa receives 3652 points of damage!
 * Hive Mind: The Big Bad calls his embryo/spider minions in Chapter 3.
 * Improbable Weapon User: A Mook uses a giant pair of pliers to kill people. Well, to be fair he uses that plier to throw chunks of rock at bullet-like speeds...
 * Journey to the Center of the Mind: The Professor and Dekoppa embark in one journey into Dekoppa's mind just to see what exactly The Majin is. It doesn't end well, naturally.
 * Licking the Blade: Not a blade, but a window. Like a dog licking a window of a butcher shop. But it's a cute doe-eyed girl who wants a pretty watch in the window. So she licks it...and her saliva melts the glass.
 * Mad Scientist: The Professor, although he is more of a Mad Surgeon playing Mix-and-Match Critters with people and demons.
 * Mate or Die: "The only reason I wanted your ass was to get at your fallopian tubes." Guh.
 * One-Winged Angel: In chapter 4, a guy goes from handsome winged angel to some kind of giant spider monster.
 * Parental Abandonment: Dekoppa's parents, presumably due to their research.
 * Petting Zoo People:.
 * The Power of Rock: Satomi's song is powerful enough to deflect a bullet from Majin's BFG. It can heal, and it can send people into their mindscape too. Plus, some of the words are actually pretty poetic. Gigantis' power is similar to this but is mainly for destruction and is not a song.
 * Red Baron: Tetsu in his gang days.
 * Screw This, I'm Outta Here: The resident Mad Scientist infecting people with the devil virus tries to flee with two assistants with coolers full of 'precious DNA samples' he used to cook up trouble. He didn't make it....
 * Shadow Pin: By demonic babies,no less!
 * Spit Take: Dekoppa, when he found out from Hayashi-sensei that Tomoe.
 * Unflinching Walk: Dekoppa vs Gigantis in the ninth chapter.
 * What Happened to the Mouse?: