|Location||Patrols the Shard edge of the western island in Desolate|
Kite Ferrus around shooting and running to the other side when he comes too close. This tactic allows you to take him out at significantly lower level. You might still need regen food in the case you fail to dodge a hit properly.
Load up some massive damage skills in your deck and fire all of those at him. Ferrus does not have a lot of HP so one or two rounds of mass damage should help him sleep with the fishes.