Eyth of Infidel may or may not actually be a god. New players are listed as adherents of Eyth until another deity is chosen. While 'worshiping' Eyth of Infidel, you are unable to ray (except in one special circumstance listed below), you will not 'catch signals from god' if wearing equipment that does so, and you will not be able to ffer anything or convert altars to Eyth's name. However, you may still have water blessed by dropping it on unaligned altars.
Infidel means 'a person with no religious faith', and the name Eyth itself may be a pun on 'atheist'. It is unknown if Eyth is merely there as a placeholder until another god is chosen, but you may still abandon your god in favor of Eyth by praying at an unaligned altar.
Eyth is still present in the same capacity in the Elona+ mod of Elona. The Preaching special action can still be used even if the player is aligned with Eyth, though NPCs won't be converted to it.