Karlia was immortal.
Her abilities prevented her from dying.
Every time her body was destroyed, it healed within a fraction of a moment. Anytime her soul was destroyed, it was replaced with a brand-new replica.
What's more, her body developed a resistance to whatever killed her initially, making her even more powerful than before.
That was the nature of her immortality.
In the Nether Realm, Karlia had suffered for what felt like eons stretching on for as long as an eternity.
Dying and dying… and dying over and over again.
The horror she experienced got to a point that common sense and conventional wisdom could not apply.
It was quite literally too much for anyone to bear.
However, since her abilities allowed her to adapt after death, she would always be revived to be much stronger than before; which would in turn cause her suffering to be increased—as designed by the Nether.