It's really a good TV series. I have a little different perspective about this story. It's not just another horror series. It's much more than that. It's a mirror of how our society is functioning. If one can ignore those gory scenes, ugly faces and high pitch sound, there is a background message in the story. Ghoul as a monster is a metaphor representing an idea or ideology (like Jihad, ISIS, religion etc). This monster is created by combination of below two sections of the society:
1) Radhika's boss represents first section that are in authority and do injustice. They are the trigger to all these horror events. They are very proud of what they are doing but don't consider the long-term impact of their actions. Eventually, there action results in creation of a monster.
2) Radihika's father represents intellectual's people of society. They are good people but are oppressed by first section. They have knowledge and ability to create an ideology(i.e. Monster i.e. Ghoul)
Some similarity that I observed:
a) Like an idea, the Ghoul can continue to exist indefinitely even after its creator's death.
b) Once Ghoul bites/eat you, it becomes like you. Similarly, once that idea takes over someone, they lose their own identity and becomes a Ghoul themselves.
c) It's difficult to identify who among us are Ghoul. Similarly, it's difficult to identify the person who sometime can be our friend, relative, colleague and is possessed by that idea.
Radhika represent people who are intellectual, brave and believe in system. They are real hero and have ability to kill monster. At the end when she kills her boss, she was not sure whether he is converted to monster or is still original human. Still she kills him because she understand that he is the real reason for creation of monster and that way is a monster himself.
At the end, the cycle begins again, when the people in authority do injustice with Radhika and sends her to jail. So, first section makes mistake again and second section again decides to create another monster.
One can question, why to show this in such a gory horror way. My answer is that the impacts of these cycles are similar to what is shown in this tv series. They kill and destroy many people lives (in much larger scale) which can be categorized as nothing but pure horror.