Grid "luckily" got a egg and hatched it and the level 1 pet was able to defeat all the other pets. It is just absurd even though the author tries to make up a very convincing reason. But the fact that Grid was able to drop one of the best pets from Hell was just way too "convenient."
It was interesting how Grid could make a master key, but that also felt like a plot armor trick
Well at first, Grid told Toban that Toban would have to be his slave, but that relationship fortunately didn't last long because Toban was behaving well and Grid "matured".
Like who cares if Grid become the general of the army, and I feel like it is just another thing that the author throws at you. Grid could have easily refused.
For example, I barely care when the MC learns the "Proliferation" skill, even though it helped him hunt. That doesn't tell me much except that he is improving and working hard. But I already know that, and the author doesn't really get too creative.