From The Heroes of Might and Magic III wiki

Most of the Conflux army is Elemental, namely:

• Air/Storm Elemental
• Water/Ice Elemental
• Fire/Energy Elemental
• Earth/Magma Elemental
• Psychic/Magic Elemental

All elemental units are unaffected by Morale, and are immune to the following spells and abilities:

• all Mind spells
• Resurrection
• Azure Dragon's Fear
• Ghost Dragon's Aging
• Zombie's Disease
• Mighty Gorgon's Death Stare
• Vampire Lord's Life Drain
• Wyvern Monarch's Poison
• Lich's/Power Lich's Death Cloud (splash)
• Pit Lord's Demon Summoning Resurrection.