Both the main characters are otakus who are taken to another world that runs on RPG mechanics along with others.
The place the heroes are summoned to even has a dedicated church and religion, telling them that they are to save the world with the gifts they acquired upon arriving.
They're given a seemingly useless class while the others get ones that are useful from the get go.
They're betrayed by a red head party member and are left alone, Took a Level in Cynic in the process, and grow stronger while they're stewing in their own anger and bitterness.
Due to this betrayal, the protagonist cares little at all about the magical world he was summoned into or the inhabitants of it. Their only desire is to return home again.
The betrayal incident resulted in the protagonist's negative reputation, though for differing reasons.
Their first party member is someone they wound up freeing from some form of imprisonment, and wound up becoming one of their closest companions and love interests.
The person in question that betrays them even puts on a public show of innocence and even blasted the protagonist in the back by an offensive spell at some point.
Bonus points for the reason behind this betrayal stems from the individual righting a personal and extremely petty wrong in their minds that centers on their dislike for the Protagonist.note For Hiyama; it's because Hajime accidentally gotten the attention of the popular girl when the latter was a social outcast that he constantly bullied. For Bitch; she desired to start a legend about herself having bested "The Devil Of The Shield" by framing him of rape.
There's even a handsome, seemingly ideal Idiot Hero that sees themselves at the epitome of righteousness and the hero as a brainwashing villain. Both also take their naïve views on the world to the point of Deconstruction in their own ways.
Two of the races are explicitly described as Demi-Humans and Beastmen, with a member of the former joining the main character as a party member and part of his harem.
And finally, all the negative events that happen in the story is due to a mortal-bornsadistic god that the main character has to deal with personally.
Everybody and his kid brother constantly going out of his way to try and claim one (or more) of Hajime's harem for himself makes sense in a sick sort of way. In Tortus, there is no mass-media. Newspapers, TV, and the Internet are non-existent. Information travels by word of mouth, so words can only spread as fast as the horses could carry them. The prevailing opinion, thanks to Ishtar and the nobles, is that Hajime is a "weak, incompetent coward" due to the fact that his Class is "Synergist" and his one Talent is "Transmute" before going into Orcus dungeon and his stats never went up significantly during training, so that's what the world at large believes. There is also a massive cultural inertia that Synergists are absolutely useless in combat. The prevailing opinion therefore is Hajime=easy pickings and so is anyone that follows him. Add to that the Fantastic Racism concerning demi-humans, for Shea, the fact that vampires are extinct for Yue, and that both Yue and Myu look like children...And the fact that Hajime's enemies seldom live to spread the word... Yeah.
There's also the fact that most Synergists had ever used their transmutation for craftsmanship, and even then, it takes an ordinary Synergist years to become a master craftsmen. By the time he got out of Orcus Labyrinth, his transformation and overpowered armaments makes him the furthest thing the Synergist was stereotyped as, but since his armaments were an absolute novelty that he rarely shows off in public, combined with the fact that Atavists are incredibly rare and the few that exists were under the Holy Church's custody, their capabilities were grossly underestimated for quite a while.
The Demi-Humans hatred of anyone capable of using innate magic (atavism) can be a bit puzzling, having in mind that other than in this, they're quite agreeable and reasonable... But this restriction is given a new light when you consider than this world kept going because Ehitorujue lacked a vessel to inhabit and be able to go to other worlds. Had they avoided killing their atavist children, there is a good chance that one of them would end up getting possessed and the world purged. This law's purpose is never properly explained, but having in mind their supportive relationship with the Liberators and the harsh treatment they received from human and devil alike, chances are its original purpose is related.
Arifureta Zero reveals that the Holy Church will take the Atavists into their custody and discards them as soon as Ehitorujue deemed that they knew too much, which is why Oscar went out of his way to hiding his abilities to avoid losing his freedom.
Beastmen who had innate magic ability was common back in the Liberator's age, and the Haltina Republic had several powerful members with atavistic traits. Holy Church had attempted to abduct Lyutilis in the past due to her ability to use Ancient Magic.
In regards of Hiyama's death, it's not something that seems like a satisfying retribution first, but the more fridge logic you apply to it, the worse it gets. Yeah, he beats the living shit out of him, but you'd think it disappointing he doesn't kill him with his own hands. Except, here's the thing: Hajime knew the situation outside, monsters running everywhere. Rather than kill him, he did to him exactly what the guy had done to Hajime: he dropped him into a den of monsters to be hunted, terrified and alone... But Hajime only destroyed any hope of escape while leaving him intact enough to prolong the time he spends in despair.
Giving a class like Synergist (a crafting class) makes perfect sense in the "game" the gods are playing. Such classes are force multipliers; the more materials their side gathers, the better they can improve the equipment of the entire party. The gods are seeing which of their pawns can pick up on this first and effectively exploit it, starting an arms race with the heretofore ignored synergists as the key to victory. This shakes up the "game board" as the older methods of powering up a faction have already been implemented as well as they can be, causing some degree of stagnation.
Them both are fairly blasphemous—Nobunaga was infamous for his fondness of blasphemy–and tend to hide behind it to justify their disruptive behavior. Hajime, for his part, also have a good reason to that.
Hajime effectively made his teacher a puppet goddess, like how Nobunaga had Daimyou Yoshiaki of Ashikaga as his own puppet daimyou. Both Aiko and Yoshiaki were drawn into trouble as a result.
He introduced the modern (if not hi-tech) firearms into Tortus, much as Oda Nobunaga was the first to use firearms in feudal Japan. Even one of Aiko's guards realized that Hajime's firearms could change the very nature of warfare in their world.
He would have annihilated the demonkin, unwitting innocents and all, during his Roaring Rampage of Revenge, if not for his adopted daughter talking him out of it (and even then, it took the rest of his party to finally bring the man down), reminiscent of Nobunaga's infamous campaign at Mt. Hiei. These events were also how they both earned the title.
He is the one to unite the whole world of Tortus together, mirroring how Nobunaga was one of the three unifiers of Japan.
Ironically, Hajime's rise into power began with a betrayal, while Nobunaga met his end with it.
The reason why most of Cattelya's monster army has the Camouflage skill is that aside from catching the Hero Party off-guard was to smuggle them inside the Orcus Labyrinth to begin with, since the Labyrinth is under Hourad, a human settlement's control.
Kaori's signature spell is shown to be Divine Shackles. Aside from it's ability to bind monsters, it can be inferred that Kaori chose to master this specific spell after Hajime fell down the Abyss, to prevent that tragedy from happening again to Hajime or anybody else she loves by using the spell to catch them.
It would make sense that Yue has quite the sexual appetite compared to the most of the girls in Hajime's harem: She's the last vampire on Tortus as her people were completely wiped out by Ehit. She hopes that the legacy of her people will live on through her and Hajime's child.
Tio has a similar kink due to Hajime awakening her S&M tendencies. While there are still survivors, the Dragonborn race are moribund and were going to meet the same fate as Yue's people. Tio wanted to find a strong male to father her own children. She got her wish.
Since the gods love to summon people from other worlds, without their consent, into Tortus "to play their chess game." Where did the demons and Demi-Humans come from?... And why haven't the gods summoned new Beast-men recently?
The origin of all humanoid species is humanity itself, it's unclear if their origin lies square on Ehitorujue, or if his fellow "gods" helped him, but all non-human species come from metamorphosis magic, and their purpose was to give Ehitorujue a suitable vessel to possess.
Despite using firearms himself, Hajime refuses to make them for any of the kingdoms in Tortus. The reason being is that it would escalate into a Lensman Arms Race that would further (d)evolve into a Tortus equivalent of a World War.
The real reason Hajime refuses to teach anybody remotely dependent on the gods how to make firearms is mostly because he can easily find himself staring down the barrel of his own creation if he made all men on the battlefield equal, especially with how Ehit can easily turn people who blindly worship him. No-brainer that Hajime would still prevail against any opposition using his weapons, but he wants to deny any advantage to his potential enemies.
The end result would still be the same. Everyone knows how dangerous a religious fanatic on Earth can be when armed with modern weaponry. Hajime's making sure that history won't repeat itself on Tortus,
