"Many years ago, a war broke out between two empires. Shinigami, with their brave warriors and spiritual power, and Orochi, with their sneaky tactics and advanced machinery, made the entire world their battlefield. Chaos had erupted all across earth."
Alternate History: The story is mainly set in Australia, where a large number of Japanese migrated to during a war. The hero's town in particular actually lives almost entirely by Japanese culture, with one of the few actual Australians in said town running a ramen stand.
Anachronism Stew: The comic was originally supposed to take place in 1950, as shown by Jack's 30's / 40's-looking radio, but the author just threw that out the window later in the very same chapter, as shown by Dr. Suno's 90's-looking computer.
Elaborate Underground Base: For starters, the entrance to the Faustian Cult's hideout is under a grave. It's also littered with traps and has many mechanical functions, including electric doors and a bridge that extends and retracts at the flip of a switch.
Friendly Local Chinatown: Tengu Town, despite being in Australia, is partly modeled after a typical Japanese city due to mostly being populated by Japanese immigrants.
Genre Roulette: Demon Blade rotates between three different genres, each one with a different protagonist. The meat of the story is the action segments, which Diablo dominates. During the mecha parts, Dr. Suno takes the spotlight, and then the Slice of Life chapters focus mainly on Michiko.
Morph Weapon: The titular weapon changes shape depending on its user.
Mukokuseki: Less severe than in many anime and manga of this genre, as the Asian characters at least have dark skin and Asian facial features. Diablo and Michiko have light skin, but they're both only half-Asian.
No Celebrities Were Harmed: Many real-world celebrities have expies in the Demon Blade universe, usually appearing as one-time cameos.
Noodle Incident: "...and that's why you should always bring a helmet whenever you visit the Honda area."
Nosebleed: Michiko has a nosebleed when Diablo takes off some of his wet clothes to restore his mobility. In the omake strip for the same chapter, she is shown with a bloody tissue in her nose while writing a yaoi fic.
Not So Different: Loki points out that Diablo is similar to the Faustian Cult, in that he only thinks of himself.
Now or Never Kiss: Hinako and Dogma, after the latter makes it perfectly clear that he's either going to kill Dios or die trying.
Our Demons Are Different: Demons aren't just a species in the Demon Blade universe; Demonism is an entire biological kingdom, and the term is used for monsters and supernatural beings as a whole. And so, two creatures who look completely and utterly different could both be called demons, just like how two entirely different creatures in the real world are both animals. However, most demons share one common weakness: Silver.
Prison Rape: Humorously subverted. Touya brings a pack of cards into his cell, and Carl insists on "making the game interesting" since he feels Touya owes him for his help. Touya is understandably horrified. Later, it turns out they're gambling for each other's food.
Product Placement: In one omake strip, the author has a bottle of Dr Pepper and a bag of Doritos (referred to as "mind fuel") with him while he draws. In another, Ivory is seen with a can of Diet Dr Pepper.
Recoil Boost: Jay uses the recoil from his dark flames to dodge an attack.
The Reveal: Dios is an evil spirit who has taken over Diablo's dead brother's body, his previous host was Emperor Keiji, he created the Demon Blade, and Diablo is adopted.
Rule of Three: The name "Bruce" is listed exactly three times in the phone book when Diablo looks up Dr. Suno's number.
Running Gag: Diablo tends to leaves things behind, but he's always interrupted by a shocking sight when he's about to say what he forgot.
Sadistic Choice: The entire reason behind Dr. Suno and Carl Baki's duel. The Faustian Cult had set it up so that no matter who wins, an innocent person dies.
Schedule Slip: The first two chapters took three months each to complete, despite being of considerably lower quality than the newer chapters. There have also been a few chapters released near the end of the month, making the monthly schedule rather loose.
It has now been over a year since the last chapter, as the author has not had time to draw due to being back in college.
Spit Take: Ivory spits up his (very hot) tea this after finding out that Diablo's story, which sounds like something a child would make up, is in fact true.
Stay in the Kitchen: Dogma tries to convince Hinako not to join in the final battle against Dios. Although, it's slightly justified, since she had just recovered from a life-threatening injury.
Stunt Casting: Heavily parodied at the end of the first casting call for the dub, which lists the names of professional voice actors cast as all but one of the characters. (that one being listed as LittleKuriboh.)
This Is for Emphasis, Bitch!: When Diablo wakes Hinako up after freeing her. He later busts out, "Don't knock it 'til you try it, bitch!" in regard to Zula underestimating his speed.
Three Faces of Eve: Among the female characters are the intelligent and serious Hinako, the innocent and naive Michiko, and the vulgar and perverted Natsuki.
Training from Hell: Diablo strongly implies that this is what Michiko will experience under him. As an example, before he could even begin to train her, he made her hit herself until it was made clear she could take pain.
Unsound Effect: The sound of Dr. Suno pulling a bonesaw from under a table? "BONESAW!"
Xanatos Gambit: Dios put Yowie in a room with a weak and easily breakable floor. If Yowie succeeds in killing any intruders, then he succeeds. If he fails, his sheer weight as he's knocked down breaks the floor and sends the intruders falling to their deaths anyway.
Xanatos Speed Chess: A wrench is thrown into Zula's plot, but that very same wrench is incorporated into it and used against the heroes.