Hoss Delgado is a "Spectral Exterminator" and a grotesque parody example of the badass antihero often found in adventure/horror films such as Ash Williams from The Evil Dead trilogy (Evil Dead, Evil Dead 2, Army of Darkness), while his appearance is a parody on Snake Plissen from Escape from New York.
He is a hunter of supernatural monsters who seems to have lost his sense of determining whether or not a supernatural creature is actually harmful, and attacks all monsters on sight including peaceful ones like Grim. He also murders people like attorneys because he does not regard them as human beings.
Billy and Mandy Movies
He is labeled as a main character in the show according to the Cartoon Network website of Billy and Mandy, despite that he's technically only a recurring character and doesn't have as much prominence as Grim, Billy, Mandy, Irwin or Billy's parents. In fact, the ending credits of "Billy & Mandy's Big Boogey Adventure" showed an image of Hoss staying home eating ice cream while having watched the whole movie on TV with a caption saying "Hoss Delgado did not appear in this movie".
In "Underfist" his never ending hostility towards monsters was put him on bad terms with both Irwin who is the protagonist of Underfist and Bun Bun, a marshmallow bunny who was the antagonist of Underfist.
Grim Adventures of Billy & Mandy
The Amazing World of Gumball
We Bare Bears
New Looney Tunes