Evil character developement

So, i have this guy who is a genetically modified human, having a magic level so high he can even take on god like creatures. His job is to hunt those creatures and kill them (just mentioning his name can make those creatures uncomfortable)

1. What kind of name should i give him? (let's say he's part from a larger group with the same powers, so what should be his job's name?)
2. How to make him give the feeling of fear?
3. How can he be defeated? (one way would be for him to die from using too much magic)
   Thanks a lot! <3

What type of power dose he have? Or do you not know? And do you already have a name for him?

1. By an inmortal ? You can create an antagonist for that character that´s inmortal and whose only job is to hunt your character.

So you don't have any appearance or personality for him? You just came up with a plot line for him and want other peoples ideas for his development?

@TheGoldenLegend his story has changed a ton, so i don't even know all the things anymore
I can create his appearance based on what he is and what he does, same goes for his name (by this i mean his personal name, like mine is Kohaku, not the title most people know him by (hunter, exorcist, etc) )
As for his personality, he's the tough, not-too-emotional guy type and cunning, bcz he needs all this to get his job done. Think of him as the supreme predator, a guy created only for an exact purpose, a living weapon.
And yes, ik i might seem like i am expecting people to just give me the answers i need (and i am really sorry if i gave you this feeling) but this guy is tricky for me, so i need a little help to point me on a certain path from which i can develop things myself
Hope i cleared some things for you