This is classically gruesome Garth Ennis.  A spoiled little kid is pinned under his obese mother when she dies of a heart attack, and literally has to eat her to survive until the police find him, days later. 

As a result, he acquires a taste for human flesh.  As an adult, he moves into the sewers and calls himself “The Man Below.”  He starts eating homeless people and living in an underground structure framed with their bones that he calls his mother.

A cult of cannibals grows up around him and becomes his personal army.

Punisher kills them all and burns the Man Below alive.

High gross factor here.