How to beat cave 5 - Use Units- Witch, Centaur, Black Knight, Succubus, Goblin, Mermaid, Use Spells - Healing, Phoenix Bird, Hercules, Athena, and Arrows. Just keep hitting forward. When your mass army is at the front of the castle and you hear the first ring, cast Athena on your melee units and Hercules on your ranged units. Use phoenix and arrows when you have less troops and want to clear out the way. Re-post if getting to the bottom.
Thanks for the comment!
 "Jenson Button F1 2010"){kind=icon}
 "Elona Shooter"){kind=icon}
 "Hero's Arms"){kind=icon}
 "Epic War 3"){kind=icon}
 "Toss the Turtle"){kind=icon}
 "Epic Battle Fantasy 2"){kind=icon}
 "Motherload"){kind=icon}
 "Terrascape"){kind=icon}
 "Game Builder"){kind=icon}
 "3D Logic"){kind=icon}