Build:Walker, Aurai Ranger

Full Build Details
You will want to have all 5 elemental boons constantly active, for which I recommend taking +3 at the Leyline and keeping an eye out for corpses in your travels; I rebuff every 2nd soul. You also will try to take advantage of every opportunity to use Brace against enemies to keep Discipline constantly active, Rage is an optional extra. (This build assumes you will have at least 6/7 of these constantly active, or I will laugh when you die a lot.)

Engaging enemies, remember one critical thing - the key to winning is not dying. You really don't need to sweat the DPS, as you'll be dealing hundreds or thousands with a well-placed skill, so the focus is on ensuring you don't die before that. Constantly circle enemies, frequently rolling thanks to your backpack, and try to position your strikes to the rear of enemies; many larger creatures have reduced frontal hitboxes which can hamper short ranged weapons like your fists.

If you get in a bad situation where your buffs drop mid-fight, Probe a few times to cause confusion and use Sweep Kick to down enemies, giving you some breathing room to beat on them with reduced damage. Infuse Wind will take your fists up to 0.96 speed, which is actually viable to fight with even if all your other buffs drop - but aside from them, don't plan on doing much swinging aside from your running attack. Counterstrike is there as another "oh poo" button for when you're forced on the defensive.

When you run into ghosts, Perfect Strike (maybe even Primed) is your answer to having to use a varnish or a rag, as it deals (base x 2)+25 in Raw damage, along with inflicting Pain.

In terms of acquiring the gear, the only difficulty is obviously the Tsar Fists, as it's gated behind the completion of Rust and Vengeance - the rest can be gathered on a run to Levant. Check the Wiki for specific details, and consider acquiring the fists on another character first.

 Running the numbers: 
 * 54 (Tsar Fists base damage)
 * x1.1 = 59.4 (Whiplash)
 * x1.97 = 117.018 (Pearlescent, Hound, Scaled Boots, Warrior Elixir, Alchemical)
 * x6 hits = 702.108
 * x2 (Prime) = 1404.216

With Dark Varnish and Possessed: (added to Flurry damage separately)
 * (59.4 * 0.2 + 15) * 1.45 = 38.976
 * x6 hits = 233.856
 * x2 (Prime) = 467.712

Total Damage (with Imbue, 6 hits, Prime): 1871.928