Build in the showcase :

Baron Rivendare Lv 14 – No talent
Banshee Lv 16 – Will of the Necropolis
Necromancer Lv19 – Jeweled Skulls
Dark Iron Miner Lv16 – Dark Iron Armaments
Bat Rider Lv15 – Flaming Pitch or Enchanted Vials
Whelp Eggs Lv 18 – Flame Burst
Harpies Lv15 – Infectious Swipes

Notes :
1.Banshee aims at Molten Giant or Earth Elemental, which greatly save your time to destroy them.

2. Most of the enemies are bombard(can’t attack flying units), that’s why Bat Rider and Harpies are in.

3. You will need a main DPS like my Necromancer which can almost defeat a tower itself. Taking over all towers before phase 2 is important.

4. Dark Iron Miner is deployes to the side that the enemy’s miner is placed. This is important to reduce the resource taken by enemies in heroic difficulty of all levels.