For this achievement you have to clear all caves in Cyrodiil. It can be a bit tricky and time consuming to clear all 18 caves because you have to kill all bosses in the caves to clear the cave. The spawn rate of the bosses can be terrible too.
Here some tips to get the achievement a bit faster:
- Only one boss spawns at a time.
- Loot everything off a boss's corpse so that it will disappear because even it's body seems to delay the other bosses spawning.
- The bosses do not spawn in any particular order. For example if you are in a cave with 3 bosses you can kill the first two bosses a few times before the last one spawns.
Here is a screenshot of Cyrodiil with all the cave locations:
For each cave you have to kill several bosses. I will post below what bosses you have to kill in each cave.
Credits to this russian site for the cave pictures:
http://forums.goha.ru/archive/index.php?t-971072.htmlBloodmayne Cave- Kill Acanthia
- Kill Ironlash
- Kill Razorback
Nisin Cave- Kill Barasatii
- Kill Volgo the Harrower
Pothole Caverns- Kill Serrin Vol
- Kill Diabolist Vethisa
- Kill Blighttooth
Breakneck Cave- Kill Hegris
- Kill Longfang
Haynote Cave- Kill Theurgist Thelas
- Kill Diabolist Volcatia
Serpent Hollow Cave- Kill Bruuke
- Kill Bear Matriarch
Kingscrest Cavern- Kill Cynaceae
Vahtacen- Kill The Faceless
Muck Valley Cavern- Kill Kerks Half-Ear
- Kill Ogre Biter
- Kill Webmistress
Newt Cave- Kill Gravel Tooth
- Kill Rock Wing
Quickwater Cave- Kill Athal Andas (Athal Andas can also spawn in the most southwestern part of the map)
- Kill Steel-Tail
Cracked Wood Cave- Kill Mebs Runnyeye
- Kill Regsrot Blacktongue
- Kill Wolfbreath
Echo CaveCapstone Cave- Kill Claudette the Sharper
Red Ruby Cave- Kill Endare
- Kill Zandur
Toadstool Hollow- Kill Lucienne Cerine
- Kill Captain Roreles
- Kill Captain Serniel
- Kill General Virane
- Kill Dreadfang
Lipsand Tarn- Kill Gaston Asham
- Kill Marbita
Underpall Cave- Kill Raelynne Ashham
- Kill Emelin the Returned