
I don’t think it’s right to blame the author for it’s inconsistency because at the very beginning when groo awakened, the system told groo they modified her intelligence/mind to an older age for the sake of her survival as an s ranker who is still too young in an adult centric hunter’s world. The comic does update quite slow so you probably forgot since it’s been a while (๑•ㅁ•๑)?

For me I interpreted the system brain modification not in IQ but more so in maturity and street smarts.
For example, the mentality is more important for survival because if you don’t have the right mentality, then all the high IQ knowledge can’t be properly used once your brain is in a constant panic. Another example I can think of is if someone is depressed, no matter how smart they are, they continue to dig a deeper hole because their head is just not in the “right space” of mind.
If it was just your average kindergarten kid having to face with what groo went through, they’d probably shit their pants. But groo didn’t panic and she faced her obstacles because the system gave her the right mentality to be able to survive anything that gets in her way even if she lacks IQ and is just a small guy. As a kid, the system taught Groo that to survive she needs a guardian, so even if her IQ isn’t high, if she follows the system’s instructions properly, her chances of survival is higher.
Love the concept but i hate how gru does not act like a 4 year old. i dont think a 4 year old child would be able to read documents and use big phrases yet?? At 1st i was like okay what if shes just a gift 4 year old. But right now im so confused because sometimes she act like a 4 year old but sometimes her language capabilities and thought process isnt like a 4 year old??? I dont think this author can write children like children. (︶︿︶)
But im enjoying the guild master's dynamic with gru right now. But im not sure if i would continue reading this because of gru's inconsistent writing.