First to download cheatengine go to http://cheatengine.org/download.php

ok now its time for the energy (mana) hack. now look at your energy to begin with and multiply that by eight and put that into the value box and click first scan. next go into battle and use energy attacks. then when the battle is done go back into cheatengine and put your energy multiplied by eight into the value box and click next scan. now change the value to 8000 and freeze it.