When Pochita (Black Chainsaw Man) manifests, it's because Denji and Pochita's contract is broken, and the state of being a hybrid is caused by said contract.
Explained it better than I could.
Also the fear scaling for Hybrids is at least quite strange because Pochita and Denji have an equal volume of fear directed towards them, and yet Denji is fodder compared to Pochita. Surely it can't just be due to a limit of the human body since base Quanxi is physically stronger than every Hybrid.
Quanxi's just built different, like Kishibe+++. Yoshida straight up calls her strength inhuman.
Anywho, despite the fact that Makima thought she was facing Hybrid Denji, when Barem notes that he's a lot weaker, Makima brings up how no one fears him, implying fear scaling does apply to Hybrids.
This also makes Makima's delulu even funnier, because she'd rather believe that a Weakened Hybrid Denji could get Double K.O. with
freaking Quanxi, than accept that she was actually facing Pochita, who
does talk and spit phlegm, and doesn't follow her headcanons about him.
Meanwhile Barem's so blindly loyal that he just went along with it. Honestly shame on Quanxi for not pointing out the issue.
Quanxi: "Hold on hold on hold on, you just said that Chainsaw Man's weaker since nobody fears him."
Makima: "Correct."
Quanxi: "And right now we're facing Denji, not the real Chainsaw Man."
Makima: "Evidently, considering that he doesn't have four arms."
Quanxi: "So then
Denji is weaker than before."
Makima: "That's how the transitive property works, yes."
Quanxi: "
Then how the f*ck did he beat Reze in one hit? One of those premises has to be wrong."
Makima: "........."