Mercenary

How to unlock: The Mercenary is unlocked after beating the game 5 times. Beating the game on Drizzle (Easiest) difficulty still counts towards unlocking him.

The Mercenary deals fast damage while dodging incoming threats. Whirlwind can be used to stay in mid-air longer. Fit skills between Blinding Assaults to maximize time spent invincible.

In the ending cutscene, the mercenary-specific text says: "..and so he left, never to become human again."

Tactics

 * A typical combo for the mercenary is to Eviscerate into a group of enemies, Whirlwind out, Blinding Assault through them and repeat for the remaining dashes followed up by another Eviscerate.
 * Try to utilize the low cooldown of Whirlwind ontop of abusing your long amount of time spent invincible.
 * Items that reduced cooldowns, such as Wicked Ring or Alien Head, are extremely effective on mercenary as they give you the ability to stay invincible nearly indefinitely.
 * Wicked Ring combined with decent critical chance is devastating against magma worms, since Whirlwind will reset it's own cooldown enabling you to literally climb up a magma worm, dealing incredible amounts of damage.