There are 4 unique codex entries in the Achievement: Epic Enemies section in Section X. They are accessible to all players regardless of class or faction.
Dreadtooth is obtained from killing the world boss which wanders around the Crumbling Wall map section.
Codex type: Achievement: Epic Enemies | Faction: Both | Class: All
Associated Achievement: Dreadtooth
Dreadtooth (Corrupted) is obtained from killing the world boss which wanders around the Crumbling Wall map section. Dreadtooth must have 3-4 stacks of Dreadful Essence which can be applied with Biochem 400.
Codex type: Achievement: Epic Enemies | Faction: Both | Class: All
Associated Achievement: Dreadtooth Corrupted
Dreadtooth (Frenzied) is obtained from killing the world boss which wanders around the Crumbling Wall map section. Dreadtooth must have 5-9 stacks of Dreadful Essence which can be applied with Biochem 400.
Codex type: Achievement: Epic Enemies | Faction: Both | Class: All
Associated Achievement: Dreadtooth Frenzied
Dreadtooth (Nightmarish) is obtained from killing the world boss which wanders around the Crumbling Wall map section. Dreadtooth must have 10 stacks of Dreadful Essence which can be applied with Biochem 400.
Codex type: Achievement: Epic Enemies | Faction: Both | Class: All
Associated Achievement: Nightmarish Dreadtooth