This is one of the more difficult waves. Focus everything on magic attacks. The most difficult player I won with was a dwarf gun-powder unit. Went like this

  1. Bannerman
  2. Bannerman
  3. Wood Elf Warrior
  4. Bannerman
  5. Fire Mage
  6. Elven Healer
  7. Elf Lion Guard

Then auto-summon some mix of Pathfinder, Fire Mage, Wood Elf Warrior, and Elven Sniper.

Research: Magic Imbuement (if you do not start with a magic weapon), Mages Imbune