Once upon a time, the King of Hell was hurt and took refuge on Earth. While he was there, a bifauxnen young lady named Chiaki took pity on him and tried to help him out. Our King Ororon promised to grant Chiaki one wish. She asked him to stay by her side forever. Being a man of his word and a man in love, Ororon did as she asked of him and then all Hell broke loose. Literally.
This manga provides examples of:
Badass Normal: Considering this universe is full of powerful angels and demons, Lika would count as a human girl who still kicks serious ass.
Beauty Mark: Ororon has three underneath his left eye. Othello has one.
Beta Couple: Lika and Shiro are very bitchy towards each other, in contrast to Chiaki and Ororon's forbidden yet oddly quiet love.
Beware the Nice Ones: Push the usually calm and collected Ororon to the brink, and you're in for a world of hurt.
Bloodier and Gorier: As the series progresses (as in by the second volume), the amount of blood n' guts shown goes up as well.
Cat Boy: Shiro and his friggen' adorable little brother Kuro. They show up initially to eat Chiaki, but end up living with her.
Conveniently an Orphan: Chiaki, and this may have something to do with the fact that her father, who was an archangel, married her mother, who was a human. It is forbidden for these two species to wed, and the punishment is execution.
Good Smoking, Evil Smoking: Many demons smoke. A few of them do not (namely, Othello, who is never shown smoking at all, though he replaces it with sex). Absolutely no demon chain-smokes to the extent that their king does. Ororon began smoking at age 15, is now 123, and is rarely shown without a cigarette in his mouth.
Interspecies Romance: Two. One between a half-angel and the King of Hell, a demon. The other is between a human and a demon cat boy.
Jive Turkey: Some characters drop select "street-jive" words like "dig" every so often. One isolated instance results in a crowning moment of funny when huge, stone like monsters are summoned by Ororon to kill everyone. The monsters initially speak in Ye Olde Butcherede Englishe when addressing the King of Hell, but when they argue over who will do the most killing, one shouts "Both y'all a bunch of slap-monkeys. I OWN this shit!!"
Man of Wealth and Taste: Ororon and Othello both have the habit of wearing suits. While Othello wears white and is taller, he is often mistaken for Ororon as they both have light hair and moles under their eyes.
Sensible Heroes, Skimpy Villains: Demons, who are portrayed as honest if nonchalant about their various sins, tend to wear suits and long skirts. The majority of angels are arrogant about their supposed virtue, and often wear skimpy white dresses (they even had a crossdresser who wore lolita). Chiaki, as a half-angel, often shows some leg in shorts or miniskirts.
Ororon was a fairly sweet, quiet child who wanted his mother's love, but never got it as she was insane and resented him for looking like his father (who raped her and killed her lover), becoming the incredibly ruthless murderer that he is today.
Othello was a well-established playboy before he reached puberty, and while it was tempered by him being devoted to his wife and child, he lost all boundaries and grew distant with his son after being forced to kill his wife or be killed himself.