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 naive 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.
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 fond of blasphemy, especilly when they 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, Nobunaga have Daimyou Yoshiaki of Ashikaga as his own puppet daimyou, too. Both Yoshiaki and Aiko were similarly drawn into trouble as a result.
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.