Aura

Credits

This page is directly copied from the old Steam guide written by many players including Dodecahedron, Shadowings, Danwulfe and credited to others in the community. The guide is taken down but recovered using waybackmachine. link: https://web.archive.org/web/20211203082144/https://steamcommunity.com/sharedfiles/filedetails/?id=2318779110

Rule of Thumb

Here's a good rule about auras: Those with the same name don't stack (with the exception of Leviathan's aura that stacks twice), and when a unit is upgraded, the aura's name changes with it. For example, you can apply Leech (Butcher's aura) and Cannibalism (Head Chef's aura) to the same unit, and each other.

This rule also applies to the following merceneries, Hermit, Safety Mole, and Pack Leader. Sending more than one of each is counterproductive, as their auras won't stack.

It's not efficient to use auras with cheaper units. Making a 700 gold unit (upgraded T6) 5% more effective is a gain of 35 gold while buffing a 100 gold unit by 5% only gives 5 gold! Aura units also aren't very strong by themselves, as their strength lies in buffing up those around it. For these reasons it's not advised to start with an aura unit.

Aura

Auras Butcher/Head Chef + Banana Haven, Green Devil, Fatalizer, Arctaire, Sovereign, Doppelganger and Hydra. Full or Off-Tanks with average to fast attacks. Alpha Male can also be paired with a Butcher, but if upgraded, Alpha Male may eat the Head Chef. This allows the units to live longer and thanks to the life stealing, killing more or the entirety of the wave.

An ideal Butcher placement in the above example, would be in the bottom left square so both the Doppelgangers get the aura from the Head Chef, and Butcher.

White Mane + King Claw, Green Devil, Antler, Hydra, Kingpin, Fatalizer, Doppelganger, Sovereign, Soul/Hell Gate and Golem. Essentially providing more bulk to your frontline, but can also be applied to your DPS units so they can survive longer.

Leviathan + Violet, Fenix, Canopie, Tempest, Sky Queen and Lord of Death (Undead Dragon/Thanatos are affected by Leviathan's buff as of patch 8.05). Leviathan's ability specifically boosts the DPS of flying units, allowing them to clear the wave quicker.

Leviathan also stacks twice, so can place another Leviathan with the Sky Queens so they can get two stacks of Aerial Command. In particular, in the first example you can upgrade the Tempests to the right, but on the last example you can also place more Harpies on the sides of the Leviathans.

Starcaller + Violet, Harbringer, Priestess of the Abyss, Hades, Pegasus, Fenix, Sky Queen and Hell Gate. Essentially anything that regenerates mana during the battle - Extra Note: Fenix is an odd one as sometimes you want it's mana to go low for that dps boost. Allows mana based units to trigger their spell more often.

Ocean Templer + Kingclaw, Sovereign, Green Devil, Sand Badger (Tanks), along with units that have deminishing or start half health such as Soul/Hell Gate, Wileshroom/Canopie, Lord of Death/Hades and Gateguard/Harbringer. Ocean Templer's aura, makes them more resistant to magic damage, whilst they still recover some missing HP.

Extra Note - An Iron Scales with the Ocean Templer aura is near invincible on 14/15.

APS/MPS + Area of Effect (AoE) units like Pyros, Masked Spirit, Elite Archer or Fire Elemental. AoE units' strength comes from killing the wave quickly, meaning an APS/MPS buffs their strength immensly. It is also good with high dps single target units, most notably Millenium and Doomsday machine! Other honorable mentions are Fenix, Nightmare, Sky Queen, Kingpin Sovereign and Azeria.

An APS could also be placed in the bottom left square so two Fire Elementals can be buffed both; by the APS, and the MPS.

Alpha Male + Lioness + Canopie, Violet, Pegasus, Orchid, Leviathan, Lord of Death and Nekomata (Perfect values that work with both the Alpha Male and Lioness). The Lioness deals more dps/gold than the alpha male even at 0 stacks; at 3 stacks the hp/gold are roughly equal.

Or if you have no units of that value you can still do this to create 4 buffs for the Lioness without debuffing the Alpha Males.

Doubling Up Auras

Whitemane + Head Chef/Butcher + Doppelganger, Hades, Harbringers and Hell Gates. Turn your high DPS into units into off-tanks/bruisers.

Whitemane + Starcaller + Hell Gate, Harbringer and Hades (Summoners). Very quick summons that become off-tanks/bruisers. You can expand on this further adding Steeds/Pegasus into the mix for even quicker summons.

Head Chef/Butcher + Starcaller + Hell Gate, Harbringer and Hades (Summoners), Violets, Kingclaw (Tankier mana users). Units that can use their ability more often thanks to the combination of lifesteal and a quicker mana generation. Head Chef itself also uses mana to get it's secondary heal, so this will happen more often thanks to the Starcaller aura.

Other Buffs and Units

Steed/Pegasus + Bounty Hunter, Hades, Harbringer, Sky Queen, Hell Gate, Atom, Fire Archer, Dark Mage, and Starcaller. Allows these units to gain mana at an increased rate, whilst Angler/Bounty Hunter keeps the mana it gains from the Steed/Pegasus.

Be aware of the anti-synergy of Protons in this setup as they'll eat up the mana preventing higher priority targets getting the mana blessing.

Dark Mage + Fenix, Nightmare and Doomsday Machine. Very similar to the APS/MPS aura to allow your damage dealing units to get more attacks in, however it's limited by mana and time but not an aura making it more effective with high cost units.

Dark Mage + Head Chef/Butcher + Fenix, Doppelganger. High damaging units that replinish HP quickly. This is a combination that not only increases the attack speed of the units, but they also steal life at a quicker rate.

Red-Eyes + Fire Elemental, Pyro, Deathcaps (AoE). Since you're playing for the AoE, Red-Eyes help deal significiant damage to the wave thanks to the splash, whilst also tanking for the rest of the AoE damage.

Rogue Wave + Fire Elemental, Pyro, Deathcaps (AoE). This allows the AoE to deal more damage thanks to Rogue Wave's Delusion debuffing units hit by its' attack.

Desert Pilgrim/Lost Chieftain + Whitemane, Hero, and Ocean Templar (Damage Reduction). This essentially buffs the heal of the Desert Pilgrim due to the increased damage reduction but also buffs the furthest target in range with a flat HP boost from Lost Chieftain.

Deepcoiler + Pyro and Deathcaps (AoE). This is due to the Hermit being the most common counter to an AoE build and with a Deepcoiler in the correct positioning it will snipe the Hermit preventing it countering the AoE damage of your roll.