Utilize Angry Chickens on the left side to effectively eliminate Banshees, regardless of their level.
Deploy Bandits or Pilots on the right side to counter the Banshees.
Remember that Banshees will respawn after 45 seconds, so have low-cost units or spells ready to handle them or use Unbounds.
Deploy an Unbound tank, such as Earth Elemental or Quillboar, behind your main minis just before they reach the boss’s attack range. This will protect your key units from taking damage.
Spamming Unbound minis and spells is an effective strategy.
S.A.F.E. Pilot with “Gnomish Cloaking Device” is particularly useful as it inflicts landing damage and at least one basic attack. Consider summoning an Unbound tank right before the pilot’s attack lands to maximize damage.
Whelp Eggs with “Flame Burst” are also exceptional and can be used similarly to the S.A.F.E. Pilot strategy.
Execute is the most damaging spell against the boss, followed by Arcane Blasts, and then Blizzard. Keep this in mind when using spells for maximum impact.