From LSWiki

Entropy Resistance is DEAD! R.I.P. It isn't here anymore. Don't bother looking for it in-game.

Class: Resistance Skills
Attribute: Vitality
Pedagogy: Body Alteration
Practitioner Term: Entropy Resistor
Hidden Skill

This skill represents the conditioning of one's body to resist being damaged by entropy and essences that partake of its nature.

Entropy resistance can be increased by exposure to entropy, changing more quickly according to one's somatic adaptability.  It will
decay over time, weakening more quickly according to one's somatic adaptability.

See Also: entropy affinity

Notes

Trainers

Temple of Discordia: Erasmus
Association:
the Stalkers of the Gate: Kalyxes
Guild:
Quest: