This quest is total hell, I am writing this guide to help people who have this hell in front of them. You probably understand why this quest is so important, Without it you can't become a dragoon :c This quest is the quest before the final Lancer quest which gives you a dragoon stone that you can equip. This quest involves 2 fights, the awards for this quest aren't really perfect either. The rewards aren't so great, A awesome skill... but wait a second you can't use it in a dungeon for some unknown reason... and oh yeah some clothes that you can buy for 1,000 gil. The weapon probably for 4,000 gil.
-THE FIRST FIGHT-
When I started this quest, I was in a big hurry. I wanted to become a dragoon, this quest was one of the things that stopped me from doing so :c The first fight, was total hell. In the first fight you have 4 Lindwurms to kill. 2 Lindwurms are attacking a guy on the ground called Thibain which doesn't help. Because lancers aren't healers and if he dies you lose the fight. When you start the fight 2 Lindwurms will run up to you and start attacking you, their skills luckily show you were they will hit so you can dodge them. But it's still hell as you need to run quickly. 2 other Lindwurms will start attacking Thibain so you need to pay attention to his HP bar, if it starts getting low, use cure on him (Which you can get from conjurer's class and cross-skill it to your lancer class). I still call it hell though, I managed to do it without Hi-Potions or any Potions or even cure. My method was... I put all skills with lowest recast time first and the ones with highest last. I spammed the lowest recast time skills at the Lindwurms like crazy, I managed to kill the 2 Lindwurms quickly and attack each of the 2 other Lindwurms which were attacking Thibain to make them run after me. To not die I started running around in circles waiting for my health to go up a bit, and then fight them again. I done this over and over again till I killed all of them.
--THE SECOND FIGHT--
Remember the creepy guy called Foulques? The one that went into the forest? He survived and he thinks if he beats you, he is gonna be the best lancerer in the whole world. So of course in the same quest they manage to annoy you like hell and make you fight him too. All for a small reward, but what can you do? You need that dragoon stone :c For this battle you definitely need cure, You will get this skill at level 2 in conjurer's class. Remember don't overuse the skill in the battle, You don't want to run out of mana! First I figured out that Foulques is a idiot. If you run around in circles he won't try to take a shortcut and attack you he will run in circles after you, which is hilerious. Don't tell Square Enix this we don't want them to make this fight any harder x.x So when he starts attacking, just run to the back of him and start spamming skills to attack him, when you see your health going down alot use cure. And run around in circles for a while. Foulques is obsessed I REPEAT IS OBSESSED with ring of ice, it creates a giant ring on the floor which you need to avoid. But guess what, even if its nearly in the middle of the battlefield and you can only run around in smaller circles, don't worry Foulques is stupid enough to still follow you. Keep curing yourself and attacking him, repeat this though the whole battle. Though he will summon three Spurned Souls they have low HP so don't worry. You have to kill the three Spurned Souls before attacking Foulques again, so be sure to kill them first and remember always use cure. But don't over use it, you need cure for the Spurned Souls as their attacks can be quiet strong. Take advantage of the fact that Foulques runs after you and doesn't take a shortcut to attack you, so while you run in circles your HP should go up.
Good Luck ^_^