Yes i can confirm it too, Undead Prince Rurik does use 100 Blades.
But it sucks you get it at the end of game becuase well its a PvE skill, and whats the point of a PvE skill when the game is over.

.
It has no good use in PvP.
I hope they put it put it somewhere earlier in the game again such as the boss near Piken's, so people can acutally use it as they play.