Tweaked version of The Dungeon Defender's Build, (I ran into issues with boss 1 shotting towers on my alt with lower stats so I tweaked it a little) They still get hit sometimes but the boss dies before they are destroyed.

Build Order - Auras > Ev reflects/buff beam > Warden during first wave from mana dropped by TB > golem start of second wave then switch back to warden for tower damage buff
(I havent tested too much, just a couple runs. but you may not need golem if your towers have some hp [this helps with build speed, instead of golem add another den])

4 du buff beam in center of bridge

***Den stack is closer to South crystal so It keeps line of sight of boss.*** 

Markers - Blue Arrows = Direction of Clouds

I run 4 heroes the whole time. 1Tower Booster, 1 Warden Builder, 2 Summoners ( 2Rate and 2Range Guardians)
(to prevent alot of lag, when the build is finished, I press F8 to only show main split during waves)