First of all, the setting and premise. It is actually just another generic premise where a person is transported in another world, on a world he initially knows at that, thus, a cheating ability immediately comes into fruition. So great! Although that is the case, at least it has been made such that it has a lot of potential, albeit really annoying. The protagonist was transported into the body of the 2nd to the weakest demon lord. Although it was not explained if his physical strength/attributes can be improved, the intellect he was shown to possess is very much already a good potential. Fighting those stronger than you with wits is an enjoyable ride, maybe even more enjoyable than Death Note if done excellently (I doubt it, though). The protagonist also has a really bad family problem that he had chosen to abandon because of his personality, which could be the main theme of this series, the effects of bad parenting. The setting of the presentation of this theme is very bad-written though. Not plausible at all.

Second, the plot of the 1st volume. The 1st volume is basically introducing the setting, themes, and characters. The themes and setting is already said in the premise so the processs/presentation of these things will just be the one discussed (what I remember). The protagonist is transported in a world, but before that, the readers are hinted that he is a smart person. The ordeal he had to pass was used as a confirmation of this speculation. This is actually not bad, honestly speaking. But the way it was presented is bad since the characters he was forced to defeat are conveniently s*upid. People who will sympathise with a demon lord. The excuse of this was supposedly because his acting skills are spectacular. I call bullsh*t on this one. That is a s*upid excuse. Furthermore, throughout the story, you can clearly see that due to the setting, he already has an edge over the others, his knowledge about the world and its future, i.e., he is cheating. Great way of forcibly destroying my expectation for it to be at least half as good as death note. Also, his arguments are, most of the times, fallacious. Appeal to the majority, emotion, etc. So obvious. I really can't appreciate this even if it shows how good he is at manipulating people since duh, it is basically indirectly teaching people how to argue fallaciously. On the bright side, at least it said that it was fallacious, e.g. It said majority logic. I just don't know if people will get it.

Third, the characters. The main protagonist is a psychopath and/or sociopath. Although it was excused that it was because of the environment he grew up with, it is still not plausible. Although the novel is already trying to explain things thoroughly, it was still not explained that well to called as plausible. You just do not become a psychopath because you have family problems. The current heroine is at least decent. She at least has her own goals and quite the smart one, too. A pity her wits was defeated by the protagonist cheater. She is shown as an emotional person, though. Although it makes you curious on what her true personality is, in the long run, if she is not given permanent true emotions, it will be detrimental. The other characters are presented either as one (or two; only the goblin was shown/hinted as a somewhat 2d char) dimensional in the mean time but, at least, the majority already are shown to have convictions in their actions. I hope they are further fleshed out and presented to be 3 dimensional characters in the next volumes.

Last, the narrative style. Don't want to comment much here. It is both good and bad. Good since multiple perspectives. Bad since bad presentation.

Falling in love with the Lala. Nothing wrong with this but MC basically dances in her palm the entirety of volume 2. Uhhh, you're the demon lord. What happened to Lala being a lowly half? Where does she get off being so disobedient.

He allows someone he befriends that is humane/against s*avery but allows Lala to kill him. ??? Are we not going to talk about this? I know he's a demon now but there's no input from his human perspective. It comes across very strange.

He rescues a s*ave to lead an army to lead a war against humanity. I guess we're dropping being a NEET now? Furthermore, she's exceedingly cruel--more cruel than probably how tr*sh he describes the 72nd demon lord in volume 1.

"I don't like people that look like kids."

>Proceeds to f*ck loli. Okay then. I also guess demons don't care about harems? I wish some discussion went into this though but Lala just doesn't care I guess.