This has been removed from Heroes of the Storm. 
Tier 4 (Hero Level 10)
Mana: 50
Cooldown: 45 seconds
Your Basic Attacks cause you to charge at enemies and have 20% increased Attack Speed. Lasts for 4 seconds.
Patch changes[]
(Patch February 2, 2016) Note: Range increased by approximately 37%; A range indicator will now display while Shadow Assault is active, and when hovering the cursor over the Ability icon; Duration reduced from 6 to 4 seconds; Mana cost reduced from 100 to 50; Cooldown decreased from 100 to 45 seconds.
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