The opponent was indeed a Mutant Beast that resembled a dog.
This allowed him to breathe a sigh of relief.
It meant that Mutant Beasts were not easily tamed unless they had an emotional foundation with their owner. Plus, with the dog being domesticated over many years and naturally close to humans, it was possible to form a one-to-one bond between a person and a Mutant Beast.
However, he couldn't understand why the Greyhound had transformed into a poisonous dog with such a bizarre form.
In Brian's previous life, the Greyhound was actually referred to as a 'Delicate Dog'—the type with a long snout and a tall, slender body with long legs.
These animals were hunters, known for their incredible speed and ability to dynamically spot prey originating from the Middle East with strong athletic abilities.
Normally, even if mutated, the beast should have transformed into something speed-based.