This achievement is gained upon defeating the following rare monsters in Accursed Temple of Cazic-Thule:

a barbed scale piranha
a blood claw raptor
a blood fin piranha
a crystaline mass
a diamond scale piranha
a disciple of Thule
a diseased mosquito
Dismay
Dreadfang
an enraged Amygdalan
an enraged disciple
an enraged jungle raptor
an enraged tiger raptor
an envenomed hunter
a frenzied shiverback
Frightchaser
a gelatinous mass
a graystriped mosquito
a gyrating mass
a noxious jungle spider
an ooze covered ritualist
a poisonstrand hunter
a quivering mass
a razor fin piranha
a razor tooth piranha
a rotting horror
a rotting shiverback
Silverfang
a silverflank shiverback
Soul Siphon
a swirling black mass
a swirling green mass
a swirling red mass
a Tae Ew aggressor
a Tae Ew bloodfiend
a Tae Ew convert
a Tae Ew hunter
a Tae Ew prophet
a Tae Ew spear fisher
a Tae Ew trapper
a Tae Ew warlord
a Tae Ew warmaster
Terrorclaw
a Thul Tae Ew adept
a Thul Tae Ew crusader
a Thul Tae Ew despoiler
a Thul Tae Ew ritualist
a Thul Tae Ew spirtcaller
a Thul Tae Ew torturer
a toxic jungle hunter
Toxiferious
a virulent mosquito

Hidden Steps

• Accursed Temple of Cazic-Thule - Availability