Spectre

Mercurial the Spectre is a melee Agility hero adept at dealing pure damage to lone targets and is powerful, both offensively and defensively. Her mobility is outrageous thanks to her Spectral Dagger which allows her to pass through objects, units and terrain while slowing her foes that came in contact with the shadowy path left by her Spectral Dagger. Desolate allows her to inflict high pure damage to enemy heroes, when she catches them alone. Dispersion reduces and reflects all damage, whether by attacks or spells, to an area around her as pure damage. Dispersion gives her great durability, especially when equipped with items that boost her health, armor, or that provides damage block. Finally, her Haunt creates a malevolent spectral illusion to all enemy heroes in the map. Haunt lets Spectre wreak havoc in clashes and ganks, while her allies take advantage of the confusion. Spectre can use Reality during the Haunt, instantly teleporting her to her illusion to take its form. This lets her hound her victim anywhere the map. Mercurial is a dangerous supernatural being, relentless as she can chase and stalk down her victim to a global range, unhindered by boundaries. She is an excellent carry and tank thanks to her incredible abilities. It is best to face Spectre with allied help and strength, as encountering her alone isn't the best option and those who are weak will just be failures of their efforts.

Trivia

 * The name Mercurial most likely comes from the DeviantART account of Kenneth Tan, the person who made the 6.28-6.32 loadscreen.
 * "Mercurial" means "swift, shrewd, and deceitful", which is attributed to the Roman god of thieves, Mercury, as Spectre is an agile and quick Hero. It also means to that of the planet Mercury, since Spectre is an otherworldly entity. Mercurial also mean "quicksilver" and of the element Mercury or Hydroargentum which mean "water silver"), which refers to Mercurial's quickness and mobility.
 * Spectre's alternate/fun name "Qwerty-" was given to spectre for remembering a Legendary Dota player Zaven "Qwerty" Terminasov, who died on December 5, 2010.
 * Spectre's voice responses are overlayed with the same track playing backwards, bearing a huge similarity to the Avatar of Vengeance's voice in Warcraft III: Frozen Throne, which was also Spectre's hero model in DotA.