There are 7 unique codex entry in the Lore section on Ossus. 6 are accessible to all players regardless of class or faction and 1 is faction specific.
Darth Malgus Lives is obtained from interacting with the Imperial Drop during "Infiltration" mission as an Imperial player or speaking with Darth Malora during "The Final Conflagration" mission as an Republic player.
Codex type: Lore | Faction: Both | Class: All
Associated Achievement: None
Survivors of the Cron Supernova is obtained from interacting with a Clickable Bedroll.
Codex type: Lore | Faction: Both | Class: All
Associated Achievement: None
The Epic of the Exiled Knight: Part Four is obtained from interacting with a Clickable Book.
Codex type: Lore | Faction: Both | Class: All
Associated Achievement: None
The Epic of the Exiled Knight: Part One is obtained from interacting with a Clickable Book.
Codex type: Lore | Faction: Both | Class: All
Associated Achievement: None
The Epic of the Exiled Knight: Part Seventeen is obtained from interacting with a Clickable Book.
Codex type: Lore | Faction: Both | Class: All
Associated Achievement: None
The Epic of the Exiled Knight: Part Twelve is obtained from interacting with a Clickable Book.
Codex type: Lore | Faction: Both | Class: All
Associated Achievement: None
Twi'lek Pilgrims on Ossus is obtained from interacting with a Clickable Datapad.
Codex type: Lore | Faction: Republic | Class: All
Associated Achievement: None