I mean, she purposefully sent him on 6 month wild goose chase that caused him to miss the birth of his children and even if she didn't go through with it, she intended to murder his wife... thats not something that can be light heartily brushed off, yet everything is immediately forgiven and forgotten, what she did goes beyond cutesy imotto antics.

Starting good with Arel not having a class and beating some swordsman, after that he starts training by replicating the moves from his mother and one of the swordsman which he defeated, after 5 years he is going in sword city where a girl wants him to join her guild but he disagrees at first, after that he wants to join a guild but no one wants him because he is classless so the girls with whom he met keeps pursuing him and he agrees, after he fights with the swordsman from back in his because (she) wants "revenge" and she got beaten they talked about a competition for their plot with the first guild in which Arel defeats 10 people of which whom 4 of them had been a -class, after that "competition" a tournament is begining with all the swordsman in which the MC after winning 3 rounds is getting trapped in a dungeon in which he fights against a puppet of the superior class [Sword God] and after he defeats the puppet he goes back in the city to continue the final round against the guild master of the first guild in the city. Because the guild leader couldn't defeat Arel he used a Demon Sword and unleash a Oni King which controlled him and got beaten by Arel, then the people shouted that the Sword God is back and thats how the first Volume ends.

After he gets home from Sword City he doesn't know what to do and is getting bored so he decides to tell his father that he wants to learn magic, so his father teaches Arel magic after Arel shows him that even people without a class have magic power, after 3 years he is going into Magic City to enroll in Magic Academy (i dont know its name) where he goes to test in all 6 departments which are [Red - Blue - Green - Yellow - Black - Light] corresponding with [Fire - Water/Ice - Wind - Earth (Golems) - Dark Magic (Necromancy, etc) - Purify/Healing (not sure). At the testing ground there were Mithril (I think) Dolls which were all "destroyed" by him, more in depth at the Red testing ground he molts the Doll, at the Blue testing ground he impales the doll with 40 Ice Something, at the Green testing grounds he does a Tornado at the doll and destroys it (i think), the Black one did not have any testing ground so he passed instantly because no one went to the Black, and at the Yellow and Light I dont think it mentions the test in the novel but it only says that he passed. After some time in the academy he went and did his 2nd grade exam faster because the "teacher" (i forgot the exact name) acknowledged him. In depth at the Red department he did a text exam and a fight exam, at the Blue department he went against the teacher and won, at green he did a flying competition with the other students and won first place, at the Earth department he fought against the teacher again but this time with golems and won agian, at the Light department he went somewhere (i dont know the exact location) and was needed to go outside while purifying undeads, ghouls, zombie, etc, at the Dark department I dont know the exact thing but while reading a book with no name he found a marquis demon and subdued it those putting a s*ave mark on it. After that it comes the Mage Competition in which all the departments send disciple to fight against each other, but everyone sent Arel because he was the best in every department. Because the Dark department Headmaster was infuriated at how small of resources he gets he summons a slime (Gluttony Slime) from the Netherworld, which of course Aerl defeats with Mage God abilities and subdues it those becoming his second "monster", after that the 6 headmaster ask him how to become a mage god so he tells them that they need to be able to use advanced magic in every Nature. And that is how the Volume 2 is ending.

In his way to home Aerl stops at a town which tests your class and gives you "nobility rank" with the class you have, going from 1 to 6, because Aerl is classless he gets 6 and after some conflict with a second rank he defeated every person in the city and he leaves, after that comes a person which is calling herself Empress because that is her class and want to see Aerl so she sends 4 of her Imperial Generals after him and they get defeated. After that he goes to the castle and and "intrudes" it and seeing his big sister being the empress which he already guessed after that she wants to marry him so she uses power and bla bla bla so he leaves and goes home where he begins to talk with his father, after some time he tells his father that he wants to become a monster trainer so he goes to a monster trainer city and want to enter a guild but he sees that to enter a guild you need at least 5 monster, so he goes to a dangerous zone and subdues one of the mythic creature (a Behemoth), after that he goes to the sea and subdues another mythic creature (Leviathan), after that he goes "in the sky" and subdues another mythic creature (Phoenix), which all of them can transform in humans, after that he goes back and enters the guild in time for the monster tamer competition which he wins by using every monster 1 round each and goes back home. And here is the end of Volume 3.

I don't have many things to say about this volume because I skipped 2/3 of it but I can at least tell some things from the end and start. So he goes home and fights with Raina (the swordsman from back then) and wins again and so he can tell Raina to do one thing for him and asks her what thing would she want him to do for her, so she tells him that she would like to get married with him and they get married, after that its time for her little sister to get tested which flees from home so he searches for her. After this I skipped much and know that the demon lord got revived so he with his son and daughter (twins I think) go to the demon castle, he lets Ark and Layla (his kids) to fight the demons and he fights with the demon lord which he overpowers and after that it just ends with the demon lord saying that he dosent want to het resurrected again and goes in a eternal sleep. And that is the ending of Volume 4 and you can say the whole novel at this point because Volume 5 is just some trivial matters.

We start by going in Ark perspective which he came from another world and sees his parents etc, after that Aerl starts and trains him and Layla at the age 1, then at the age of 5 they go and slain a Orc and after that Layla says she want to become stronger and Aerl say that next one will be a Wyvern. And thats how it ends, of course thats how the first 3 chapter end because I dont know the rest.

Chapter 29 basically reveals that it's not a harem. Personally I thought the author was joking when we saw the hints appearing. Hence why I'm left feeling that this is a joke. And since I feel the final pick was shoehorned (he never expressed an ounce of romantic interest in her except for her tits. The few times that she shows up, she's been complaining the whole time. This is grounds for a marriage?!),

... yeah, I'm not willing to trick myself anymore.

Here's the truth, it's not just the MC that is shallow, it's everything. World. Support characters. Lore. Even the Training montage. Bleh! 凸 (｀^´) "

got married with the arc after with the whole sister chase and after that

One of them just gets forgotten and the other starts going for her nephew ????

Later he has twin child now Ark and Layla, and he trains them. The story focuses on childs later.

once his son took over as the main character I felt like the quality of the storytelling really dropped. At first it wasn't that bad, the idea that his son was actually transmigrated was interesting in my opinion, but he quickly showed himself to be useless his personality was, with how much he let his sister completely control his life with barely any resistance from him, let her clean up all his messes with the "bullies" when it would have been so much more satisfying to see them slowly learn how OP he actually was and realize themselves "Maybe we shouldn't mess with this guy", and quickly devolved into the stereotypical "Lucky Pervert" cliche with the princess when it actually could have been an interesting romance. Author completely ruined a good series.

1. Swordsman arc, 2. Magician arc, 3. Tamer arc, 4. Little sister "rescue" arc, 5. Training kids arc, and 6. Son pov arc