Here are examples of the word/phrase "vulnerability" used in a sentence and paraphrased in a sentence...
Even though Kalel has a vulnerability to magic, he can still hold his own against it.
Even though Kalel has a susceptibility to magic, he can still hold his own against it.
The crimson gem may have granted Cain physical invulnerability, but his mind has a vulnerability to psychic techniques.
The crimson gem may have granted Cain physical invulnerability, but his mind has a susceptibility to psychic techniques.
That deity may seem virtually invincible, but he has one vulnerability.
That deity may seem virtually invincible, but he has one susceptibility.
Other Examples...