With good stealth and assassination tools, Ash is a deadly Warframe, capable of inflicting massive damage on the battlefield.
Ash’s passive is Hemorrhage. All bleed effects inflicted by Ash on his enemies deal more damage and last longer.
Ash’s fourth ability is Blade Storm. Ash creates multiple clones that will strike marked enemies. When you first activate Blade Storm you will enter targeting mode. During this mode just move your aim reticle over enemies to mark them for assassination, each one will gain one death mark. Staring at an enemy longer or moving the reticle over him one more time, will mark him again.
Each enemy can have a maximum of three death marks. Marking an enemy costs energy but if Ash is under the effect of Smoke Screen this cost is reduced. Using Blade Storm again will activate it. Clones of Ash will teleport between marked enemies, using finisher attacks on them for heavy damage and inflicting a damage over time bleed effect on them. Each strike against an enemy will consume one death mark. While the clones are attacking the marked targets, Ash can cast Teleport, at no energy cost, on a marked target to join Blade Storm, becoming invulnerable while striking his enemies. All strikes done by Ash and his clones during Blade Storm count towards Ash’s melee combo counter and the damage they inflict bypasses armor.
Ability Strength mods affect the damage of Shuriken and Blade Storm. Additionally, Blade Storm’s damage is affected by the melee combo multiplier and its animation speed is affected by melee attack speed mods. Melee damage mods on your equipped melee weapon do not affect this ability, however, the aura mod that increases melee damage does work. Ways to make enemies take extra damage from finisher attacks also affect the damage they take from this ability. Ability Range mods affect Smoke Screen’s stagger radius, Teleport’s range and the range from where you can mark targets with Blade Storm. Ability Duration mods affect the duration of Smoke Screen.
So, all things considered, here are some builds you may want to try on your Ash: