Could my Adnaps exist?

Question

I imagined a hypothetical mammalian species of the Cetartiodactyla order and of the Ruminantia suborder: adnaps. They are the opposite of giant pandas: if giant pandas are vegetarian carnivores (they mostly consume bamboo and fruit, but they have the digestive system of a hypercarnivore), adnaps are meatarian herbivores (they mostly scavenge other tetrapods, but they have the digestive system of a ruminant). They are my ogres. Some basic characteristic of my adnaps include:

1. Are as solitary as polar bears;
2. Are as nomadic as great white sharks;
3. Are mostly scavengers, but they sometimes act as ambush predators, and exceptionally as pursuit predators;
4. Despite their reputation as the only carnivorous mammal of the Ruminantia clade, they will exceptionally eat herbs, leaves, and fruits;
5. Females weigh an average of 200 kilograms (440 pounds), and are 8 to 12 % smaller than males;
6. Have an average lifespan of 24 years, and have a slow metabolism;
7. Compared to humans, they have a better sense of smell, and a better sense of eyesight, but they do have a worse sense of taste (they cannot taste sweet, and umami, they only taste bitter, sour, fat, and salty), and a worse sense of hearing;
8. They mostly live in East Asia (mainly in China, but not in Japan), but they can sometimes be found in South-East Asia (like Thailand), Central Asia (like Kazakhstan), and exceptionally in South Asia (like India);
9. They have pig-level intelligence;
10. They are both extremely poor climbers (like elephants) and extremely poor swimmers (like giraffes).

Given these characteristics, what species could they have evolved from, and what evolutionary pressures would lead to them?

Answer 1

Oh deer!

Imagine a scenario where there's a massive increase in aggressive small mammals. They attack other small animals, even of the same species. Sometimes they kill for fun. These critters move almost silently. Imagine the rabbit from Monty Python as an example.

How would existing animals react? Over a long enough period of time, evolution would prioritize large size (the angry bunnies don't attack large animals) and deprioritize a sense of hearing. There would be a lot of dead animals lying around from the bunny killing sprees. So there would be evolutionary pressure to scavenge dead animals.

Under these pressures, it's possible that deer could evolve into adnaps. Deer are known to eat meat in rare occasions. National Geographic reports that a deer was even seen scavenging a human corpse. And natural selection can be quite effective at increasing the size of a species in only a few generations.

Answer 2

Turns out It's Man

You are looking at one my friend. Your creature sounds like a human being. A mostly herbivorous ape that can survive eating only meat and vitamin C pills.

Bonus points for starting from a gorilla-like animal. That is suitable since these AdNaps are ogres. I believe gorillas have a bacterial chamber in their stomach to ferment boatloads of vegetation, similar to ruminant.