After accepting the quest, head west out of Katan and follow the road for some time in a northwestern direction until you reach the Sinking Swamps. Kill Finnedman throughout the Sinking Swamps until you have collected enough eggs. Return to Adventure Guide Firia with the eggs.
(You hand over the Finneden's eggs. Firia cracks one open and takes a bite.)
...U-uuagghhhh! PFFATHFFF! Wow, these are nasty! I've never tasted something so gross in my life! YECH! UGH! Hurry up and choose your reward, I need to wash my mouth out!"