Anthropomorphic Personification

An anthropomorphic personification is an idea that is given 'life' as a human being or other humanoid...though some animals may count as well. The essence of the idea is that it's a concept that has been put into a form that can interact with the world.

A classic example of an anthropomorphic personification is the western 'Death' figure: the Grim Reaper. Another would be the idea of 'Mother Nature' as a woman: representing life on earth.

Any general concept can be easily personified: you can create a character that is the humanoid form of a storm, or the humanoid form of winter, or the humanoid form of a species of animal.

The difference between a run-of-the-mill anthropomorphic character is that an anthro character is, say, merely a humanoid kangaroo, whereas an anthropomorphic personification of the kangaroo is intended to represent all kangaroos everywhere. Some continua make this rule more complex (Let's not talk about the Death of Rats) but that rule holds: An anthropomorphic character represents only an individual, but an anthropomorphic personification represents a concept.

Most of the time, these special beings are more powerful than 'normal' characters and may have powers or duties related to the concept they are the humanoid manifestation of.

Anthropomorphic Personifications in Canon
A few examples:

Anthropomorphic personifications are quite common in canons: many gods in ancient pagan religions or even characters in folklore are something along the lines of an anthropomorphic personification: a 'sun god' and a 'moon god' would often not just be in charge of the sun and moon, but would be the sun and moon, too.

Discworld has many anthropomorphic personifications that hold semi-deific status, famously including Death.

Calypso from Pirates of the Caribbean is both the Goddess of the Sea but also literally the sea itself, so she counts as an anthropomorphic personification.

Hetalia and its various works is about anthropomorphic personification of countries.

Narnia has a Father Time.

The characters of Tron and Reboot are personifications of various program functions found in computers.

Uncle Sam is supposed to be an Anthropomorphic personification of The United States of America.

It is a common incidence in Japanese media to personify a product, group, or other concept, called a gijinka. Canon ones are often not entirely serious: often advertisements or jokes. Fandom gijinkas exist for everything from computer operating systems to every single Pokémon ever released.

Anthropomorphic Personifications in Fandom
Literally being death itself is cool. There are many Mary Sues and Gary Stus who would like to believe they are death itself. Or 'light' itself. Or 'blood' itself. Or any number of cool concepts. Being an anthropomorphic personification in a continua where they do not exist can be a charge if it's obviously done as an excuse to have cool powers related to the concept they are modeling. Many wannabe-Deaths like to pretend to be all dark and mysterious when they carry scythes, but may not actually understand fully the implications of being death.

(Like any character type, an anthropomorphic personification can be good if executed skillfully and thoughtfully.)

In continua that already have anthropomorphic personifications, it is bad if an original character tries to be a concept that already has a personification. For example, in Hetalia it is bad to make another France, or to put a second personification of the ocean in Pirates of the Caribbean when Calypso already is the personification of the ocean.

Anthropomorphic Personifications and the PPC
The only known Anthropomorphic Personification to work for the PPC is Agent Death (here). More specifically, the Death of TV Shows. She continues to do her old job, as well as take on PPC missions.

However, the PPC does come in contact with these beings from time to time and they may be the object of badfic.

It is important to note that Neuralyzers do not work on certain anthropomorphic concepts such as Death, Winter, or Time. These are concepts that don't have any natural mental faculties of their own, and as such, cannot be forced to forget anything. Discworld's Death is a notorious example. However, personifications of human-created groups certainly are able to be neuralyzed. Follow this example:

Death, Summer, Sleep, and Rain do not forget. Man, America, Christianity, and PETA can forget. It is unknown if The Internet is able to forget, but I wouldn't think about that too hard.

Devising, finding, or creating an anthropomorphic personification of The PPC would probably be a very bad idea.