To trigger this new boss battle, you must interact with Aldia at specific locations in game.
Normally Aldia can be first encountered in the room of the last primal bonfire you light. Aldia can be found in the following locations with additional dialogue:
- Undead Crypt
- Dragon Shrine
- Throne of Want (after killing Nashandra - requires death of Vendrick)
If all primal bonfires had been previously lit prior to downloading the latest 1.10 patch, Aldia will first appear in the Black Gulch. After exhausting his dialogue, he will move to the first bonfire in the Undead Crypt . From there, Aldia will move to the Dragon Shrine near the first bonfire. After interacting with him at the Dragon Shrine, Aldia will appear in the Throne of Want at Drangleic Castle immediately after you kill Nashandra as another boss.
Please note that it is required to kill Vendrick to trigger this second Aldia boss battle.