End Game Cards

Vampiric Blade - Shatter Golem - Guard Piercer 

Build Path

Put one point into Agility to obtain Cull the weak. 

Farm till you have 6 points total in Agility and obtain Guard Piercer. 

If unable to gain the 5 points put 2 into Vitality and obtain Tower Strider and Living Guardian. If not max out Agility.

Continue to put points into Agility until 25 and switch out Tower Strider and Living Guardian for cards such as: Nitro Boost, Overclocked Droid (If 2 in Vitality), Heavy Hitter and finally Shatter Golem.

Once you have 25 points in Agility get 6 points into Vitality and remove a card (Not Guard Piercer and Shatter Golem) and obtain Vampiric Blade.

All 3 cards max out to 25 Agility and 6 Vitality.

Gems

Agility Gems

Slot 7 - Ruthless 
Slot 13 - Multishot or Lifesteal
Slot 19 -Piercing Basic
Slot 25 - Relentless Assault or Critical Hits

Vitality Gems

Slot 1 - Quick Exit
Slot 7 - Damage Reduction