The following is IGN’s guide to the bounty hunt A Behemoth Undertaking aka Deadeye, in Final Fantasy XV.
Deadeye has been terrorizing the people and creatures nearby the Wiz Chocobo Post. It’s up to Noctis and his friends to slay the beast. Head to the entrance of the grove near Wiz’s to track down the beast. Most of what you’ll be doing will be trekking through thick fog and killing a few weaker daemons until you find Deadeye.
Once you’ve tracked him down, follow him to his lair and slay him. Fire attacks work especially well by destroying the oil drums near him. Return to Wiz once you’re finished.