There are Summoners on each stack (3 Summoners) all equipped with the apprentice and huntress guardian pets combo.
Made for a friend to match their stats. I ran this 4 times through and it held steady. It's slowish because of the lack of damage, but it works. The north aura takes a beating compared to all the others because of how the spawns and scenery is positioned. It does last all of Wave 35 with about 400 health out of 2100 by the end. Higher warden tower damage output will speed things along and keep the auras healthier, meaning less health is needed for the auras if there is more damage. Also this is assuming the auras do not overlap with the east mob spawn doors, or else that will drain the auras too fast and slow down the run a lot.
Nature Pylon is positioned to buff all the auras.