I'm a level 33 on Epic Duel and with this build, I've had 2565 wins and only 72 losses in the last month. 
When you're in a battle, you want to start with Venom Strike.  Once your opponent has been poisoned, then you only really need to strike after that although you want to use your Sidearm and Auxiliary as much as you can.  Hope that this helped.   :D



Stats

Health: 89
Energy: 45

Strength: 60
Dexterity: 50
Technology: 40
Support: 40



Skill Tree
1 Field Medic
1 Smokescreen
1 Cheap Shot
10 Bloodlust
1 Reflex Boost
10 Venom Strike
10 Shadow Arts
1 Massacre  (only use this in your in a 2VS2 situation and an ally gives you energy. Don't rely on this to save you.)



Equipment
Main: Royal Cleavers - Hank (Fortune City)     12'651 Credits   0 Varium
Sidearm: HyperTalon - Overlord Guard ( Overlord Facility)     12'000 Credits   0 Varium
Auxiliary: Neutron Blaster - Zedmyr (The Bazaar)     12'000 Credits   0 Varium
Armour: Preadator Armour EM/EF (Level 28) - Overlord Guard ( Overlord Facility)     19'000 Credits   0 Varium