This is just my opinion:
But i watched the 1st video, i don't see anything. @5.13 it was 2x double dmg hits, maybe even with ignore, @6.03 - 6.13 he stopped hitting you and changed targets, @8.10 lol, combo..
Didn't even bother to watch more.
You have to understand he is FULL BK (not like Flippy, who says he is "full"), just look at the char on web - DP+all+14, 2x BB+15+all, W4+15+all, Demon, Pend+all, ring+all (both fire, so he gets decreased dmg from DL's..) + 129 achievements+power buff + 20++% from set buff + vip buff + guild buff + he has MS/elf buff all the time + of course the main factor - he is BK. BK is the strongest char if you remember..
This is just my opinion, so don't flood with answers.
Higher ppl will take a look and will give the final answer.