Arrow storm is the variant from drag mag.
I was explaining where the 80 arrows a round come from, since you seemed puzzle.
Time stand still with 10 level of eternal blade can effectively grant you 4 full attacks in 1 round. With the right feats, you can even do 2 of those before everyone else acts in the round (except celerity mages)
You can take kensai if you want to... but eternal blade is gonna be better all around: bypassing DR, free knowledge checks, insta maneuvers if you need them, int to damage, uncanny dodge, int to AC.
Kensai gets nothing compared to eternal blade.
Blood in the water, with improved critical, gets really good the more attacks you have, because it is not precision damage, even on an undead, if you confirm a crit, you don't get additional crit damage, but you do get the +1 to attack, +1 to damage every time you confirm a crit, that can quickly rise up, since they don't go away as long as you crit in the next minute. It's a pretty good stance to have.
And don't get me wrong, you can do whatever the hell you want with your build, i don't really care.