This achievement is gained upon defeating the following rare monsters in The Temple of Droga:

Blood Ritualist Taprom
Bone Caller Nathid
Bone Caster Fizzik
Bone Knight Runri
Bone Trooper Grolin
Cave Guardian Prehtil
Death Ritualist Stromik
Dirt Criminal Vakov
Dirt Defender Gropp
Dust Hoodlum Heaprit
Earth Mystic Gedak
Earth Seer Gamolk
a fierce drogan spider
Flame Adept Verdalix
Flame Master Japal
Ice Adept Amozik
Ice Master Cialin
Jailor Maufan
King Dronan
Magic Adept Xabok
Moss Knight Yortal
Rock Sneak Nrillip
a savage drogan spider
Slinker Ukul
Stalag Trooper Biamas
Stone Crook Piklo
Stone Seer Kaigek
Whip Cracker Krazzim

Hidden Steps

• The Temple of Droga (Enhanced) - Availability