Answer:
Diction is a very useful tool for the writer to form the character. It is also the choice of vocabulary inherent in a particular writer or speaker, as well as the style of expression in a song or story.
When the writer wants to create a monstrous character, he/she will choose a vocabulary full of words that can describe evil, fear, strength or cruel to use them to give the character some physical or psychologically characteristics. It can also be described using a metaphor, allegory, grotesque to make a character scarier. Also, the words that character uses can be wrong spelled to show ( if the character is some kind of monster) that he is not human, or the character can use only vocals to shout or yell them and become scarier.
The monstrous character can be devised as a person who has evil intentions and is introduced with adjectives that are bringing the atmosphere of fear. Diction is powerful because it can express the smallest details important for building a character.