This "parasite" was clearly a very powerful monster.
As a 'biological weapon', it had two forms: First, it had the original form of a metal ball. The second was the combat form that evolved according to the host's body.
In its original form, the parasite had an excellent "erosion" ability. With this power, it could parasitize the bodies of most living creatures ... Even an official-level existence like urdini would find it difficult to resist.
Of course, this didn't mean that the parasite's ability would also work when it encountered a real official ...
For the parasite's "corruption" to succeed, it also required a prerequisite. If the parasite's mind and body reached a certain strength, or if they had a certain special attribute, the corruption would fail.