Actually retarded. Everything's so fucking messy I feel insulted. First, why did the noble's men so easily betray him? They even posed and were always by his side, go to beat up MC and after losing they just fess up everything, why? I mean sure, you lost, but that's literal treason.
Then, magic. I can understand magic making your body harder, but why's your sword sharper? If anything, it should be duller, since it's covered in hard steel-like magic. Also steel shouldn't be able to cut orichalcum. If it could, then the noble would be wearing steel, since it's (I assume) cheap and strong.
Finally, MC. Man, you are seriously in another level. If you can't change the story, then DON'T CHANGE IT. WHY would you stop the noble's assention to power if it's cannon? Your main purpose is to not stray. If you're going to do what you want, don't say "oh, I have to protect the story" also don't you think that cutting orichalcum in fucking half is kinda noticeable? And surrounded by people, to a noble everyone knows, while the knight captain and other nobles are looking? To top that off, he cut JUST the armor without touching him, wich shows amazing ability. I don´t know what I expected, I'll just drop this. Fucking low tier slop, it makes me angry to know stories like this get read at all.