Slark

Slark the Nightcrawler is a melee agility ganker and semi-carry with extremely high mobility and damage potential, capable of stealing stats on auto-attacks to boost his own damage while remaining unseen even while attacking. His signature skill, Shadow Dance, provides him a period of invisibility that doesn't end upon casting spells or attacking, thus, he can freely strike upon his foes without fear of retaliation as long as his enemies do not have True Sight of him. It also provides him with a high rate of health regeneration (over twice the rate of Heart of Tarrasque) and movement speed boost, as long as he remains out of enemy vision. He can also deal AOE damage with Dark Pact, which also doubles as a purge skill; on the other hand, Slark weakly damages himself upon casting it. Essence Shift is what makes Slark fearsome if left unattended - each of Slark's attacks will reduce the target's stats and convert it to an Agility boost for himself, enhancing both his damage, attack speed and armor while weakening his target.

Tips

 * If you are low on HP before level 6, try to avoid being attacked and then take advantage of your ultimate's passive healing ability.
 * When being chased, always pass through woods. Blindspots let your ultimate's passive work in the middle of the chase.
 * Taking advantage of bonus attack speed from both Mask of Madness and Essence Shift, Skull Basher later built into Abyssal is a good item on Slark.
 * Pounce is both a chasing skill and escape mechanism for it's "leap".