Best Girl is the demon tribe princess (she shows up in later chapters) and she is absolutely deserved to be with the MC, unless the author exists. Yes, her ultimate rival is the author himself. She is the one who spends the most time interacting in a romantic way with MC, her character development and romance development with MC is the most complete and understandable, even the MC himself thinks that she would be the first one for him to marry (Yeah, not the ultra beautiful and OP teacher that would become useless later in the novel). Her personality is so lovable every time she meets MC (unlike those "all hail MC" types) and she is even willing to sacrifice her vitality (yes it's to that extent) to save the humans related to MC when the feud between the demon tribe and the martial school of MC occurs. But guess what, MC can't marry her because it would cause a huge issue with the demon tribe and even when that problem is solved, he is too busy with his "duty" to strengthen himself in order to protect his harem of mostly human girls who was OP but now become useless (in terms of power, not money - and yes, all the harem girls now have lots of $$) since the power level is now raised above theirs while author is too busy focusing on keeping the antagonists alive and bsing more artifacts for MC to collect. Yeah, no sexy time for you, bastard MC -quoted from author's inner sadistic voice. Anonymous reader: "I heard from somewhere that he got married" Yes, he did since author decided to troll all the readers when introducing a demi-human girl who was absolutely despised by the beastmen in the series just by existing but she is a "saintess" from a beastmen sect so they can't kill her; while MC and her got involved "accidentally" on this trip to find some artifact, she and him got drugged with an extremely strong aphrodisiac by a "wingman [with author's name inserted here]" which they have to mate since all their cultivation would disappear forever from fighting against the drug. (Yeah, how convenient but then MC is fated for a life of no s*x after) Later, they would marry because there is this marriage-only martial scroll that allow MC and this girl to become stronger on this journey for power, but since MC and the girl fit the qualification (after long arcs of fighting of course), they marry since they also know each other and MC wants to take responsibility from taking her v*rginity from way back when. Yes, not to the best girl, but to this demi-human girl which less story time than her. (How nice, author - how about you write a NTR story instead). Finally, this demi-human girl's character is understandable after analyzing her background but her love development seems sadly forced compared to other girls in harem (she is discriminated by her clan, no one approaches even human because of power and race difference, MC doesn't, forced s*x from drugs, fall in love with more encounters?)

Why does MC doesn't kill this bastard that literally is below tr*sh and is persistent to the point that he shows up wherever MC goes (either treasure hunting or collecting artifacts or even buying rare materials) but instead throws him into a portal that "probably kills him as well as any other beings"; then, after long arcs of story, he shows up to be even stronger than MC because he receives training from another higher being? Or that MC only half-kills him and let his clan take him in for treatment and later he would show up again being more powerful?

at c1250, MC already surpasses about 99% of this realm or plane that he lives in and he needs to go to another realm where he threw the antagonist bastard into (yes, he threw him into a higher plane) to gain even more artifacts and strength because he discovers later that the guy that he didn't kill is planning to make all the higher beings descend and conquer the lower realm since literally, anyone from higher realm can rival the strongest of lower realm without much problem. Yes, don't think that the Higher Tian masters of the martial school will even save the realm; they don't have the power to. "This is not even related to power levels" Yes, it does, because as of c1250, author has to spend time creating more classes that are higher than "Ancient Supreme Tian" is what I believed it was called and it is a pain trying to remember all of these names when you want to know who's stronger than whom. Back to the Ancient Tian, they are so strong when they were alive that even their artifacts in their tombs can help fighting which is why you will see MC in the future collecting these. But why even bother remembering since the higher beings have better artifacts and more power?