Our WAR pulls in Defiance because I had issues holding aggro without staying Shield Oath for longer than the duration of Unchained, basically, so it was a DPS gain to swap to our WAR pulling.

So, basically, I spend probably a grand total for 45s (maybe) in the whole fight in Shield Oath. I provoke and take the double hand cleaves and tethers in Shield Oath, and the rest I just Sword Oath. Sheltron is incredibly strong in this fight as far as tanking, and you should have a CD up for every single cleave you take.