Nep’s fellow Legionary has been turned to stone. See Kistig, an alchemist in Morheim, and ask him for a way to break the curse.
Step 1. Go to Morheim and talk to KistigA Daeva who studied alchemy at the Crystal Rise in Morheim until rampaging spirits forced him out. He would like to continue his studies..
Step 2. Go back to Gelkmaros and talk to NepA member of the Pandaemonium Expeditionary Force stationed in the Gelkmaros Fortress. He gives his whole heart into whatever he believes in..