Iga's Rock Spell:
Once the "Shingan Hoo" spell (rock spell) is cast on enemies, the "Taimakoodan" spell (laser spell) is enabled/accessible. The laser will attack all the enemies under the rock spell. Note that the Taimakoodan spell is not usable independently.

Chongara's Secret Character:
Chongara also has a secret character that he can summon at only certain times. To access her, you must fight your way through all 50 dungeon levels at Alalatos, and eventually fight her. If you do manage to defeat her (good luck -- you'll need it), she will join your party and Chongara will be able to summon her, but only in certain locations.

But then, you have to go UP through ALL the 50 levels again, in order to get out. If you die, all the hours of work will have gone towards nothing! So be sure to be well prepared before going down there.