Creating an Intimidating Villain

[thethreetearedeye]

I've been working on a book series, and just finished book 8. The main villain of the story is always in the background and their perspective is view in the Epilogue of each story. In the past, they've dusted cops (literally turning them to ash), sucked the life from animals to fuel their life force (long story, the villain is a corpse animated by an ancient god trapped inside it), and when the main characters finally encounter him, the don't even defeat him. The villain sees an opportunity for cultivating the MC to its grand plan and leaves them be to return at a later date when his plan is ready.
This was all "Arc One" of the story. I've started the next Arc of the story line, and while this undead god is still the big bad of the series, the villain of this arch is a mimic that was supposed to replace the MC and steal her life. However, the mimic fails but again, the big bad sees potential use for the mimic.
The epilogues of Arc Two are from this mimic's perspective, and book 8 closes with the mimic meeting their god essentially.
The problem is, this mimic has developed a strong sense of self, which is useless to the god. In their interaction, I tried to make the god feel possessive and cold. While it would be in character for the god to outright kill a failure, it also finds the unique nature of the mimic's sense of self interesting and wants to manipulate that.
I just don't know if I've conveyed how evil the big bad is in the writing without making it super obvious. I'll include a excerpt so you see what I mean.
Any feed back is appreciated.

".... She could smell rot, the decay of meat so strong she could have gagged. But the stench ran deeper, as if the very essence of this man was rancid.
When the figure spoke, the words felt like knives in her eardrums.
“Now, is that any way to talk to your God? Kneel.”
Each syllable peeled apart her mind. The authority, the control, was undeniable. She collapsed to her knees. Her hands began to tremble. Never in her short life had she been so scared.
Unbridled joy and crippling fear overwhelmed her as the eight fingered stranger loomed over her. She couldn’t understand the conflict, her brain grappling with loose threads as the figure regarded her. Its gloved hand gripped her face, holding her chin roughly in its broad grasp. Cruel fingers dug into her skin, twisting her head so that the figure could inspect her left eye.
“I’m interested,” the figure said, “The Toad is much stronger than the last I checked on it. You were doomed to fail from the start. However, I’m fascinated by what you might accomplish. The circumstances of your creation are unique. You aren’t like my other mimics. Despite your failure, I believe I have some use for you yet. You have a new task.”
She nodded, her eyes streaming with soundless tears. She just wanted to be let go. The tips of the figure’s fingers hurt, even through the brown leather gloves. It was a touch that had never shown tenderness or love..."

[MikeDwight]

I guess... What if the villain just blindly yells about what it thinks you are for 10 years with no input. I mean that's nearly identical in the situation there. Villains lash around about circumstances they're in and there's convenience in projected enemies around, Batman you lecherous swine.

[Backstroke_Italics]

I think there are a few ways to improve your example.

First, basic description writing. Your perspective character's nose is somehow able to detect that a smell is in "the man's essence." That's quite a sniffer! The reader cannot follow her on that journey because our noses only smell what people smell like on the outside. Maybe think about more concrete examples. You ever been on a long-haul flight, and there was turbulence, and somebody's bag of sick from four hours ago splashed up and over the heads of the people in the next row? Neither have I, but by God I'm smelling it right now, a lot more vividly than I can smell a person's rancid essence.

Second, show don't tell. We really shouldn't need to be told the villain is evil. We want to know what the villain is doing, how he is impeding or targeting the good guys. That's where you show us the evil. A description like this should really be about what the villain is doing at the moment. This is why those cheesy villain monologues usually happen while the villain is turning the big crank that releases the acid into the city streets, or casually eating children's eyeballs or something.

Third, subtlety is scary. Don't try to make the villain more evil by turning the evil stuff up to eleven. Try turning it down to the level of a whisper. I guarantee you "his voice sounded like honey in her ears" will creep your reader out more than "his voice sounded like knives in her ears." Truly scary villains always tip the waiter.

[Theglasshouse]

Make the bad guy evil, and prove the good guy is good. The villains are for some reason always more sinister. They have evil plans. They take drastic measures that make people suffer. There's a reason bad villains look uglier.

Aristotle's principles in poetics suggests this and more.

Also, consider both character's perspectives. What is each thinking? What do they both want? How does that make one the villain and not the other? How does this goal make the other villain look bad and evil? For example Chinatown which is full of examples. A rich person wants to secure the water supply of a Los Angeles water plant for himself.

His methods are bad too since he murders people and nearly kills the protagonist. He hires henchmen to kill him.

I know it is a movie. Maybe such violence needs not be in a short story. But maybe it could be present in a novel.

[thethreetearedeye]

For context, the MC of the series is striving to be a monster hunter, the last in her family. She has the weight of the legacy on her shoulders and she wants to live up to it and be as successful as her ancestors have been. The main villain is a god from another reality that dimension hops, infecting universes with dark magic by combining their spirit and physical worlds together. This is a cataclysmic event, and the god reshapes the universe he destroyed in his image and moves on to the next dimension. However, the family of monster hunters the MC is a part of crippled the god, binding his spirit into the physical world. The god has been sowing chaos to have his monsters do the work for him while he killed off the family one by one. The MC doesn't know the full history of these events yet, but knows she is definitely the last of her family to hunt monsters and she knows what the god is capable of.
The context of Arc Two, which this question is focused on, involves the god and one of his monsters, a mimic he created to weed out the MC, kill, or replace her. The mimic is special, as it became infected with direct contact with the god's dark magic while it was developing from its "original", and has a greater will to survive. The mimic wants her own identity and life, and sees the only way to achieve this is to follow her god's directions so she can fulfill her instinctual purpose of replacing the MC. However, the god makes it very clear she is a pawn and disposable, and she is bound into the god's service, which she grows to despise.
So to break it down:
MC wants to protect the world from monsters and follow in her family's footsteps.
Villain wants to destroy the universe and recreate it in his own image.
Mimic (Arc Two's main villain) wants to find a life for herself, free from the influence of her creator.