Look at the second video again for gods sake once defense down has been cleansed watch when asajj uses special and after that. WATCH PROPERLY A HIT FROM ASAJJ WITHOUT DEFENSE DOWN SHOULD CLEAR NIHILUS PROTECTION. I HAVE DONE THIS RAID FOR 6 MONTHS I KNOW THE MECHANICS.
Hey @najwa2012 - I watched the video. When your Nightsisters (including Ventress) hit Nihilus, his purple protection bar clearly drops.
However, given how little it drops, the conclusion is that over the course of the battle, you have allowed him to drain so much protection that his max protection is probably in the millions. And whenever he takes a turn or consumes some minions, he heals a certain percentage - which is why you see his bar go up around the 1 minute mark after he took another turn.
Without seeing the entire battle, it's impossible to determine exactly what happened, but the end result is that Nihilus' protection is so large that you will need to chain dozens of hits in a row just to reach his health pool.
Edit - attached a screenshot of a very high scoring NS run. The run scored 10.5M points, but if you add up each character's scores, they did a total of 4.2 Million damage to protection. Given that Nihilus' protection bar rarely fills up above 10%, that means his protection bar likely was over 5M max protection! This means that there are ways for Nihilus' protection to become astronomically high - and this screenshot is from a run where Nihilus had plague for most of the battle.
