Dreadful Legend - Lestallum
First Available: Chapter 15
Other Requirements: Complete A Legend is Born
Rewards: 10,000 EXP & Dragoon Lance
This quest begins after completing A Legend is Born from Randolph in Lestallum. Much like A Legend is Born, this quest is part of a quest chain (all given by Randolph) which reward you with various "ultimate weapons". For this quest you will need to travel north of Lestallum to the Vesperpool area where you'll have to fight Malboro enemies.
Warning: A Timed Quest where you have to fight 9 Bandersnatches (3 at a time) takes place in the same exact area on the 3rd day of the month (real life time).
You'll find one big Malbodoom here along with a small group of Malboro Brats. Take out the Malboro Brats first as they have much less HP and can be quite the annoyance. With all of them defeated you're safe to focus on the Malboro boss. Avoid getting in front of him as best as possible to avoid his Bad Breath attack which (similar to other Final Fantasy games) inflicts tons of status ailments onto you.
High level magics work well against these enemies too, if you choose to melee this guy be sure to be well stocked with consumables. You'll be using quite a few! Once you're done return to Randolph and speak with him to turn in the quest, he'll now give you the followup quest Legend Wrapped in Enigma.