I like everything except the bit with norman’s father. He does not deserve mercy when dude cheated on his wife, treated his son like trash, left his other son with a terrible woman and only came to him for his magic, and let his daughter be abused.The manga’s ending is not that bad though.
Actually, I think the parts drastically changed by the manga is much better than the WN.
For exampleWe’re spared from a lot of Crocell and Focalor’s harem member catfight for Norman’s attention.
Focalor didn’t even give him any trial like the storm to test his character. She just fall for his negotiation that because she wants to be like angel who guide people to good, he will do it together with her.
The WN didn’t put Norman as hardworking like how the manga started. It’s just the usual trope of a plain guy being condemned for being talentless. Even the teacher is telling him to give up. Manga’s version teacher and Regal is much more sympathetic, not cardboard villain.
The demons like Norman because he is talented in commanding demons, not because his pure soul. So Norman’s alignment is opposite, he’s good in the manga, and seems to be evil in the WN.
The demon summoning pace is much slower. While in the manga we did have some one-off demons like the crow when he need to rebuild his house... the WN version summoned more demons with battle ability, so the battle scenes often turns into Norman repeatedly invoking the demons like card game monsters.
Meanwhile, in the manga, he can use the elemental power from the sigil without having to invoke the demon’s name each time.
Jellyfish is in the manga only.
Vassago’s arc is manga only.
WN’s Regal is really just a cheap antagonist.
In the WN, he got an older brother he respected, but after finding out his brother is bullied in the school and try to hide it from the family, he is traumatised and decide he will not be weak. When seeing Norman unable to use magic, it reminds him of his brother, and he decide to bully Norman.
After he lost to Norman (not draw), he felt his position is threatened as people begin to think he’s weak. So he tried to bully Dimitri, but again got beaten by Dimitri in duel.
There are multiple Ars Goetia created when a candidate for king appears.
Also the ending in the manga at least give a closure.
In the WN version, the fight against Billeth is done without summoning Asmoday.
Norman still managed to hide the fact he is summoning demons.
His father came to beg him to return. Norman accept, with the condition that his father would help to cover up the fact he is commanding demons. Norman still plan to rule over all the 72 demons.
In the manga version.
Esland family is stripped from their nobility and wealth after many witnessed the family’s two sons are using demon. Dimitri is left unconscious after the possession, while Norman is let off the hook with only getting expelled.
Regal offered to marry Nene, and in exchange his family will take over all Esland’s assets under them. This means he can at least let Norman’s father and sister living as before.
Foscal explained, the demons want to took down god, and give a world of no suffering to human. Norman can be their commander against god. But Norman rejected it, preferring a world where human can experience and overcome difficulties. Thus, the demons leave him, he can’t fulfil their wish. Orobas is the one who felt most betrayed, because he likes human, but his summoner betrayed him.
Because the demons had left him, Norman begin to hear voice of the spirits. And because he’s blacklisted, he is planning to study abroad.