The crystal foci?  Of course we'll explain it seeing as you only have half the brain power to figure it out.$B$BA depleted crystal focus can be combined with ten apexis shards in a simple process, which creates a charged crystal focus.  These charged foci have some healing properties, but more important is their use with a possessed demon.$B$BYou see, the charged focus can be used to enable a possessed demon to exhibit special powers.  After a time, Gahk will have a mission for you to do just that.