Earthin

A being that comes from the outer world for example Hunter Steel. It was unknown for a long while whether the prophecy refers to him, thus it is unknown of he is destined to be Arachna's salvation or its destruction. Mantid reveals that he was an Earthen once, a chosen warrior of the Oracle, pulled against his will into the Inner World. His reason of taking the Oracle's power is revenge upon the Inner World and the Oracle herself after many losses, including his beloved. When Hunter had him at sword point, he sparred Mantid, showing him kindness. Mantid then changed back to his human form, and was reunited with his love Loraine, granted by the Oracle.

Concerning the prophecy, it says an Earthen will bring disaster to the Inner World. Sparkle and Shadow mention it in the beginning of the series, but it's not known whether the Earthen shall be their Salvation or or Destruction.