From Lineage 2 Encyclopaedia

Properties

Expose Vulnerability
Gives flesh and takes a bone. Decreases the enemy's P. Def. by momentarily exposing his weakness when receiving the enemy's attack. Increases the critical hit rate of general attacks.
Class	Soul Hound
Type	passive
Attribute	-
Recast time	0 s
Cast time	0 s
Cast range	0
Item for learning skill	Forgotten Scroll: Expose Vulnerability
Classes with same skill	Duelist, Dreadnought, Adventurer, Wind Rider, Ghost Hunter, Titan, Grand Khavatari, Fortune Seeker, Maestro, Doombringer, Soul Hound, Soul Hound-, Judicator

Skill Upgrade

Lvl. to Learn	Skill Lvl.	Description	MP Consume	HP Consume	SP
81	1	Gives flesh and takes a bone. Decreases the enemy's P. Def. by momentarily exposing his weakness when receiving the enemy's attack. Increases the critical hit rate of general attacks.	0	0	6500