The Whirlwind Assassin doesn’t exist until you obtain Chaos. Typically, once you’re in the position to use this item, you’ve already completed the game, so the Whirlwind Assassin is an endgame build. That being said, being able to Whirlwind as an Assassin is something every player should try at least once in their life!
Video Build Guide
She is definitely an expensive character to create, since Chaos requires an Ohm and an Um Rune. She also needs relatively expensive gear choices to really boost her melee Damage or successfully hybridize her build to see killspeeds similar to other melee builds.
As a build dependent upon Increased Attack Speed, Cannot Be Frozen is a must-have attribute. Raven Frost is the best way to obtain this.