There are 6 unique codex entries in the Achievement: Datacrons section on Dromund Kaas. They are faction specific.
Assembly Chamber is obtained near a proximity map trigger.
Codex type: Achievement: Datacrons | Faction: Imperial | Class: All
Associated Achievement: None
Galactic History 18: The Hutt Cataclysms is obtained from interacting with the Yellow Matrix Shard datacron.
Codex type: Achievement: Datacrons | Faction: Imperial | Class: All
Associated Achievement: Dromund Kaas Datacron Master
Galactic History 19: The Pius Dea Crusades is obtained from interacting with the +2 Red Mastery datacron.
Codex type: Achievement: Datacrons | Faction: Imperial | Class: All
Associated Achievement: Dromund Kaas Datacron Master
Galactic History 20: Chancellor Blotus is obtained from interacting with the +2 Green Endurance datacron.
Codex type: Achievement: Datacrons | Faction: Imperial | Class: All
Associated Achievement: Dromund Kaas Datacron Master
Galactic History 21: The Birth of the Mandalorians is obtained from interacting with the +2 Yellow Presence datacron.
Codex type: Achievement: Datacrons | Faction: Imperial | Class: All
Associated Achievement: Dromund Kaas Datacron Master
Galactic History 22: The Second Great Schism is obtained from interacting with the +2 Orange Mastery datacron.
Codex type: Achievement: Datacrons | Faction: Imperial | Class: All
Associated Achievement: Dromund Kaas Datacron Master