Pre 5.3 I was casually soloing Blood Lord via Ice Blocking 9 seconds into the fight, waiting for decapitate, then burning him down before the next one. Got the idea from some videos on Youtube. If you really needed the DPS you could have popped MI to trigger a bloodletting (or whatever its called) to delay the 2nd decapitate, but it didn't take crazy DPS.

And yeah use Greater Invis to skip the trash.