Here is the best Calus theme you will ever listen to! This contains all his dialogue with tormentors and DPS. I have also done one for Rhulk and Nezarec here...

Rhulk:    • Rhulk’s Theme (With Dialogue and DPS)...  
Nezarec:    • Nezarec’s Theme (With Dialogue and DP...  

Descent - 0:00
Confronting Calus - 3:24
Ending the Tormentors - 7:27
Calus' Final Stand - 10:00
The Witness Allows Calus' Death - 12:34
Long Live the Emperor - 13:20

:)