This series starts as an action fantasy, but it gets all over the place with the story. The power scale is complete clusterfuck. It’s so ludicrous at one point an “E zone” is introduced. It means the stats go over the 999999999 points where exponent notation is used instead. It reminds me of cookie clicker, but applied on shounen power levels. I gave up on the numbers long before that point given the main character starts at usual values around 100. Speaking of the main character he could be classified as typical disregarded shounen protagonist, who suddenly discovers his hidden power. It’s at this point quite overused skill of absorbing other skills from enemies usually after the MC defeats them. This time with additional ability to absorb all the stats as well. It has drawbacks, which turn to be not so serious in practice as it might be suggested initially. Mainly necessity to kill like for a vampire, who doesn’t drink blood, the thirst otherwise becomes unbearable. It was an interesting idea, but it never had any serious consequences as far as I can remember.
Fights are enjoyable, but usual shounen tropes apply, and there are a lot of them , except bit more gore given it is seinen*.
Characters are rather typical, but enjoyable still. If this ever gets anime adaptation, most people are going to be interested more with Myne, girl with the axe, or Aaron.
Visually the series looks ok.
Overall, I think this series is rather average.
Japanese difficulty 5/10 (see my profile for details about various difficulty scores)
This series is classic seinen without furigana except for introducing people. It isn’t suitable for beginners.
This review is written after reading 8 volumes (all existing at the time).
* Japanese bookwalker has tagged it as seinen
 For an example it goes or at least hints predictably the seven deadly sins trope. Obviously, the MC is gluttony.