Maou is convinced that he can eventually take over Japan (and maybe the world) by working his way up through the ranks of MgRonalds. He becomes obsessed with being the best employee he can, to the point that he seriously considered using some of his very limited remaining magic in the first episode when the fry cooker broke.
Becomes interesting once you find out that this was exactly how he rose to the top in the demon hierarchy. And when you consider that he's very patient and immortal, the plan suddenly isn't unfeasible at all.
Calling their (old and cheap) bike a Dullahan. This is done insistently and in the manner one would use for a mighty noble steed or air fortress.
Everyone acting like Maou and Emi are in a relationship. Maou is pretty indifferent to the idea, but the comedy comes from Emi's reactions. She always has very extreme reactions.
Emi and Chiho's many faces.
Anytime Miki-T is mentioned.
When one of the characters from Ente Isla gets passionate and yells, Maou (when it's not him) usually points out they are in public and then we get a beat of people staring at them.
Emi tripping on the staircase when leaving Maou's apartment.
It starts with a badass beginning, and Maou flees with his right hand man, he declares his intent to come back - and lands in Japan of all places.
Alciel's attempts to use magic always fail. The first time he tries with the police that he and Maou meet, attempting to blast them, only for nothing to happen as a police officer and Maou watch silently; next scene he is in the police car with Maou. He tries again after leaving the police, and calls a taxi.
Alciel attempts to invoke a powerful magic attack, pointing his hand at the sky and yelling.
Then Maou getting information out of the police officer talking to him by using hypnosis, then going to find Alciel. Who is eating Katsudon. They all just freeze and stare at each other, blank-faced, Alciel with Katsudon in his mouth.
Maou trying to use Japanese, which is very broken. As Alciel congratulates Maou, they have a very dramatic sounding talk in their demon language.
Maou considers trying to survive on fast food till his next paycheck, which causes Alciel to break down, asking if this is Supersize Me.
Maou taking his job at MgRonalds way more seriously than the DEMON KING should.
When Emilia comes to Maou's house to confront him, Alciel locks her out. As he and Maou explain the situation, you can hear Emilia yelling outside, banging on the walls and the door, threatening to break in, complaining about how things have been really difficult for her, and she eventually breaks down into sobbing.
When Emilia rings the doorbell and tells Alciel who she is, she tells him to "Open the door and take your judgement like a man." Cue Alciel locking the door, hooking up the security chain, and then freaking out. Not very manly, but hilarious nevertheless.
(Emilia is in MgRonalds, staring angrily at Mao. Cheerful music is playing on the MgRonald's speakers.)
(Maou maintains a cheerful smile despite Emilia's angry expression.)
Alciel: "I cannot allow you to go on a date wearing Unislo from head to toe."
Maou: "Y-you little ... Apologize to the world's #1 apparel chain and to me for that!"
The fact that Maou and Alciel listed Emi as their guarantor just because they can pisses Emi off. It also turns out that Emi faked her age but the real reason she's pissed off is because they apparently did it to cause trouble for her.
Maou: Well we could've asked my boss but...
Alciel: You don't want to cause trouble for her, do you?
Emi deflecting a magic bullet, only for it to bounce off her gauntlet and smack Maou right in the face while he's holding up the falling bridge.
Alciel being late to the fight because he went back home to get his cape.
And then it has Maou chewing Lucifer out for possibly making him late for work and missing out on his perfect attendance bonus pay.
Emi's companions limit the Idea Link to those who were constantly thinking of Maou. This includes Chiho, who blushes at the revelation and screams in shock when Maou and Alciel get back to the apartment, causing them to scream as well.
Alciel's dying words(if he died) was telling Maou to save money.
Alciel being more pissed off that Maou was spending money to watch movies, instead of the fact Lucifer had betrayed them.
Maou decides not to go back to his world, as he has a lot of shifts this month.
First Lucifer is now living with Maou and Alciel, and he is a neet. He proves that he has gone native like Maou and Alciel by hacking into Emi's computer at work. Emi's and Lucifer's faces when he does that is hilarious.
What's a power so great it was able to knock out Lucifer, Satan, and Alciel?... A photo of Mikiin a swimsuit.
Which Alciel tries to use as a weapon.
When Maou chides the others for being defeated by a photo, Lucifer dares him to look and Maou desperately tries to change the subject.
The entire plot of the episode was Lucifer tricking them into getting his Pasta(Vita) back for him. Their faces when they find out is gold.
Maou being completely oblivious to Chiho's feelings; even Alciel looks amazed by this.
Maou is afraid of haunted emails that'll take you to hell and freaks out when Lucifer calls him at that exact moment.
A Demon King who is afraid of being sent to HELL? And relaxing when he realizes the person on the other end of the line is LUCIFER, a Demon? It makes you wonder who would be on the other end of the line if the call was really meant to take Maou to hell.
Begins with Maou's expression when he takes the box of Udon from Suzuno and finding it MUCH heavier than it looks, especially when Suzuno, who is a head shorter than him, lifts it up with no trouble.
It is then quickly followed by Maou's and Alciel's reaction as Suzuno tries to pull out the letter she got with the same photo from last episode. In slow motion.
Emi finally feeling that she probably looks like someone that's stalking Alciel and Maou.
Also the identical looks on Urushihara, Emi and Ashiya's faces when Maou suggested that Suzuno work at MgRonalds.
Urushihara also silently snarks in the background.
Suzuno copying Emi in spilling the creamer, and even giving a small fist pump when she does it.
Kisaki, the MgRonalds manager, telling Maou about how one of her colleagues got reassigned to Greenland after losing sales to a rival chain. Maou's reaction after Kisaki threatened him with the same if he screwed up against Sentucky is priceless.
Ashiya's "explanation" to Rika about he and Maou's relationship with Emi, transforming the story of a deadly war between demons and humans in a magical realm into a story of corporate warfare on Earth where he and Maou were founders of an up-and-coming company Maou Inc. and were forced into bankruptcy by their rival company where Emi was its star employee.
Ashiya: "They evidently serve organic coffee."
Maou: "Coffee made from ogres?!"
Ashiya: "Organic. It means grown with natural pesticides."
When both Emi and Chiho express their dislikes for reptiles, their respective imagine spots are hilariously different - Chiho was freaked out by a small, normal lizard while Emi was desperately trying to hold off in combat against a basilisk (note the petrified warriors).
Also, Suzuno's description of lizard dishes which she tried during her time in the South in Ente Isla.
Urushihara going on an online shopping spree while Ashiya was confined to the toilet after a bad case of food poisoning.
Sadao feeling uncomfortable at the comments everyone gave about Sadao the monkey, much to Emi's amusement.
Urushihara tries to get his package but gets a leg cramp.
And the subsequent exchange when Maou receives the package instead of Urushihara:
Alciel is shown returning to his asskicking demon form in the hospital... but he arrives to the scene way too late again after the battle's already finished because he went back home to retrieve his cape again.
And he gets told that he needn't even bother if he was going to be so late.
And then he breaks down and cries.
At one point Urushihara takes some food (which Suzuno made) from the fridge, smells it, and comments that it "reeks of divine power, but food is food".
Urushihara wanting Emi's bag back, because he believes she would kill him if he didn't give it back.
Maou calls Emi flat after she dismisses his rescue of her and as always she's furious at this. Suzuno tries to change the topic, then she becomes a target of Emi's wrath. Then Maou remembers his uniform and freaks out because he's missed out on work.
In Emi's dream, she dreams that Maou has regained his powers and taken over Hatagaya. He then states he'll take over Greenland.
Beyond the random factor, the thing that makes this joke even funnier is that Maou was in danger of being sent to Greenland if he lost that fast food battle against the SFC.
Ashiya chiding Urushihara for planting a tracking device on Suzuno, not because he respects her privacy, but because he's worried about the cost of the device!
Maou chucks Sariel into the Gate and he winds up in the MgRonalds freezer.
Mitsuki falling for Mayumi and creeping her out with his usual antics.
Urushihara snarking at jealous Chiho, only for her to tell him to shut up.
Maou's reaction to discovering Urushihara fell for a purchasing scam.
Also, Urushihara's pathetic attempt at hiding the boxes.
The very fact that it was Urushihara (you know, Lucifer, a demon) who got scammed is funny in itself.
When Alciel finds out he's working for the scam company, he angsts over what he's done. Emi reminds him he was a demon general.
After they got out of the scam, Maou's face at the guy who tried to scam them is awesome.
Maou then wonders if he can convert Emi (after helping them) to his side.
Maou (who for certain reasons could not assume his demon form) needs to break through some soldiers in Ente Isla. What does he do? He smashes through them on a motorcycle, using diversionary tactics such as throwing firecrackers at them, honking the motorcycle's horn loudly at their face, flashing the motorcycle's high beam at them, spraying insect repellant at their mounts' nose, and throwing homemade (kind of) molotov cocktails at them.