Comments of chapter undefined of Leveling Endlessly with the Strongest System!

I have read another book by the author, very good. This one is quite nice. however this separation of levels is confusing. the mc is on the 13th level of the first realm, something not seen in 700 years. but a level 15 monster appears. I understand that this monster would be level 5 of the 2nd realm. but it is not clear and makes it confusing. I understand that monster only has level and not realm of cultivation. but there has to be a separation like humans. The amount of hp of the monster is also very exaggerated, mc only has 10hp, but the monster has 500hp, even if it is lvl5 from a higher realm, and a very big difference. the mc's stats were supposed to be superior to the enemies by being mastered to the maximum because of the system, but the wolves had super high stats too.