he literally asks his master to cut him with his full strength (he is a sword saint and is considered the strongest) just to raise his durability.

He even fought a God for 8 days non stop because he thought he was an exp punching bag

we have the sword saint (uncle) probably the most strongest fighter. Who has an eye for the MC for how much obsessed he is about training, and considers him unique as people in the world train to live while the MC just train for his enjoyment

we have higaki who is also crazy and tries to kill MC because her master favors the MC more than her, but later knows her mistake and how batsh*t crazy that was so she apologized but she still has an inferiority complex on the MC but later chapters just worries about the MC because of how batsh*t crazy he is

we have iris who is kind hearted and keeps counseling the MC to keep his humanity from disappearing and scolds the MC for how batsh*t crazy he is

we have louise who is a demon kin/vampire who was disguised as diva but is in an enemy organization but was coerced by the MC to give her "freedom" in exchange of cooperating with the MC. She admire's the MC for how free he is and aspires to have that much freedom

we have "the protagonist" who is also a reincarnator who believes that the gamestory should progress how it is but later realizes that butterfly effects happen and regrets it for underestimating the situation he is in

we have 'the villain" who is in an enemy organization and somehow his powers is system hacking (like cheat codes) ?? Idk details are not yet omitted in the latest chapters

First we talk about the MC. His sole motivation is to level up. He does everything efficiently to the point that people in his surroundings find him crazy. Which is actually true. He always calculates the most efficient method in everything that it is fun to watch. What I like about the MC is that he is really capable. He is not whiny and will fight if ever provoked. Though he'd rather spend the time leveling up than fighting. Unbeknownst to our MC, his obsession's for leveling up is actually causing great changes to the world he is in. Characters that should've been a kind person with strict personality becomes a psycho that points her weapon at MC's neck as long as there is a chance. This mellows out in the future. A person that should've died according to the game, lives. Event schedules in the game are accelerated. Its actually quite the spectacle to read. MC's stats are very low though since he is a mob character. To rival a level 50 protagonist he needs to be atleast 75. Which is fun to see since he never cared about the stats and just wants to level up.

Higaki. The annoying student council whose obsession is to erase MC's existence as her jealousy on why MC is the favorite student of their master clouds her vision. The first time they meet, she bashes MCs head and steals his sword. MC, not wanting to lose, trains hard to have his revenge. Eventually they kill each other during the competition. Now in the underworld they are forced to do some job to reincarnate but whenever she sees MC her vision clouds which leads to them trying to kill each other again. Eventually, they will reconcile because of some events. There she would finally see that the MC could flawlessly execute the signature move of their master. Prompting another bout of jealousy. She'll eventually realize that it was never the MC's fault and rather her lack of training that she cant execute such moves finally acknowledging MC's superiority over her. She vows then to train and eventually surpass our MC. She will then always try to assist MC and keep him in check if he is ever planning some crazy schemes. Though her sharp tongue will remain and keep criticizing the MC, She is actually one of the most loyal character to the MC. One time when MC was asking a character what her purpose was, Higakis first action was to block the door and aid MC. Another time was when MC told them to get ready for battle despite no prior warning of enemies since they are watching an opera, She instantly prepared her battle stance believing the MC's words no question asked. Her obsession to their master mellows out and for some reason she always sticks to the MC.

Amanai. A transmigrated person. Same as MC. Except not as capable. He possessed the body of the original protagonist and his obsession is actually the status quo. He wants to follow the game events to a t. This makes him view the MC as a potential threat to his goal. He remembers struggling when he played the game because of that he is afraid. He never analyzes any potential answers to problems they can resolve and would rather stick with the games answer. The only thing this guys got going for him is his body's specs and stats which is actually very high. Though he sometimes aid the MC. He is actually under levelled compared to the MC at least.