I'm surprised that people are upset about OP characters in this story. Pretty much everyone is stronger than Skele-bro . It took him how many deaths just to kill the bounty hunters in the first chapters?
He was fine in the fighting tournament because no one who was actually strong participated. They even mentioned that the guards in chapter 29 were too strong. The drunk with the rapier who whooped him in the tournament then forfeited wasn't strong enough to become a knight.
Heck if you think back to the first time Rena died, the knight back then was looking for a Necromancer. This was way back in chapter 10 or 11. Since he woke back up in the same cave that Rena died in the first time, that knight is probably still looking for the Necromancer in this incarnation of the world, in order words he's looking for Gilles. They just happened to come across Rena and those knights assumed the Rena was the necromancer. However the knight knew that she wasn't the real deal since she wasn't anywhere near strong enough.
Now we are finally seeing how strong a knight truly is in this world and people are saying it's power creep?
The knights are stronger than anyone who was in the tournament (including the drunk), yet they are weaker than the Demon Lords, but the Demon Lords lost in the end, so someone has to be stronger than the knights and the Demon Lords. We have only seen a small sample of the power levels in this series. I'm not sure what people were expecting. It was laid out pretty explicitly in the first few chapters.