Wondrous Weapon - Lestallum

First Available: Chapter 15
Other Requirements: Complete Cursed Legend
Location: Lestallum
Rewards: 20,000 EXP & Zwill Crossblades

Wondrous Weapon is the final quest in Randolph's chain and can be started immediately following completion of Cursed Legend. For this quest you need to head on over to Fort Vaullerey at night time and fight Naglfar. This will be the hardest fight yet (duh) and you'll want to make sure you're well stocked on all curatives (Hi-Potions, Elixirs, Potions).

Naglfar is a level 120 boss and is weak to fire as well as the Star of the Rogue Royal Arm that Noctis uses. I'd also strongly recommend you fill up at least four or five Magic Flasks with Fire since the majority of your damage to this boss will be through Magic or Tech/Armiger.

Much like all of the "super bosses" in Final Fantasy 15 the fight will be really stupid. You basically are in your inventory screen most of the fight using items to heal yourself and using Techs like Prompto's Piercer which makes you immune to damage during the animation. You'll get one Summon during the fight too so hopefully you get a good one.