Slark is one of the most dangerous heroes in Dota 2, and theres a good reason for that: his abilities all make him very powerful once built-up. It is possible for him to take on multiple opponents single-handedly if equipped with the right items. This danger is based off of his multiple abilities, particularly Essence Shift and Shadow Dance. Essence Shift, which takes 1 of each attribute per strike from Slark, and giving him +3 Agility, allows Slark to quickly gain considerable damage and attack speed, while at the same time weakening his enemies at a similarly rapid rate. The fact that it can last up to 120 seconds has the potential to give Slark a huge amount of bonus damage, making him even more formidable. Shadow Dance, meanwhile, protects Slark from detection and damage, and can also grant him bonus HP regeneration and 40% additional movement speed. In other words, he gets 4 free seconds to escape and heal and cannot be targeted during that period. As a result of these abilities, Slark could use a re-work, so that he doesnt gain such a huge advantage over his enemies. For example, Essence Shift could be changed to target an enemy Heros primary stat instead of all three, and Shadow Dance can be re-tooled to make Slark vulnerable to detection by some (or all) detection items available in the game. Either way, Slark is a dangerous hero that needs a re-work to make him more manageable for those who have to fight him.