Not optimized yet, but a rough plan is below:
The Reaper's Toll is the main weapon. You should be defensive here because you have no shield. (And you definitely want some DR.)
And you use conviction as your main aura, so that you don't have to worry about AR (vs bosses etc, as ITD on Reaper's Toll doesn't apply to bosses etc.)
Then you need 99 IAS for 6/6/6/6/10 attacks.
Armor: Treachery. 45ias, fade(res & DR), fhr and venom(poison dmg)
Helm: CoA(IAS/ED jewel x 2). +1, res and DR
Belt: SoE. DR, LL and MDR
Ammy: Highlord's. 20 IAS, +1, DS and light dmg (if you have Tele Amy, then use it!)
Rings: Raven Frost, Wisp(Lightning and light absorb, BK, Dwarf etc
Gloves: 10 or more IAS (LoH, Lava Gout, Bloodfist, CB gloves etc)
Boots: Gore Rider
Wait! No mana leech? Well, sock pskul into your weapon. (Or Shael and put an ML ring instead.)
Merc should use a weapon with massive elemental dmg, such as Crescent Moon, Rift, Azurewrath, Harmony, Ice etc.
Hmmm... I might make one 😆