To beat 5, I used the strategy being pasted all over. The trick is, first of all, not to use powerful cards because you're only fighting goblins. Use weaker cards that are lvl 5 so that you have LOTS of troops to spam your enemy with. The mermaids were also important - be sure to include them. At the beginning just keep your troops back and fight off the goblins runnning at you. If you keep your troops on the left of the map the bombs won't attack and it's easy enough to kill off goblins. They attack in waves so it's easy to hold them off with spells like meteor. Once you're close to having the maximum for each unit, cast a spell to get rid of the bombs and then rush in. Once at the castle, the idea is that the sheer number of troops and the mermaids' blasts will keep knocking the ghost back so he can't do much damage. Send any newly spawning troops in to replace your losses. With the aid of spells you should be able to kill the castle.
 "Epic War 3"){kind=icon}