The Ruins of Fei'Yin 5-1
Client: Gate Guard
Reward: N/A
Skippable: No
Items Needed: None
Talk to the Gate Guard in either West or East Ronfaure gate. He'll tell you to go talk to Halver in Chateau d'Oraguille. Halver will ask you to go to Fei'Yin to investigate some strange activities there. Before heading off to Fei'Yin you might want to do a couple of quests first to ensure you have maps of the surrounding areas. Her Majesty's Garden quest in Chateau d' Oraguille will give you the map of the Northlands which will be very handy. And A Smudge on One's Record quest in Windurst Waters will provide you with the map of Fei'Yin.
Head to Fei-Yin through Ranguemont Pass or Teleport-Vazhl. Enter Fei'Yin at about J-5 of Beaucedine Glacier. Once inside Fei'Yin you should recieve a cut scene. Now make your way to the BCNM fight at K-8 on the first floor of Fei'Yin. You will be fighting Archlich Taber'quoan NM skeleton with about 6-8 other skeletons. The level restriction on this BCNM fight is 50 so make sure to have level 50 gear on. This fight can be easy or hard depending on your party set up. The key to winning this fight is to go after Archlich Taber'quoan NM and kill it as fast as possible. Don't waste time on fighting the other skeletons. Once the NM is dead then the fight is over so concentrate everything on the NM. Use your 2 hour as soon as possible to inflict as much damage as possible on the NM before you get over whelm by the other skeletons. Once the NM is dead, head back to Halver to complete the mission.

 
The Shadow Lord 5-2
Client: Gate Guard
Reward: Rank 6 & 20 000 gil
Skippable: No
Items Needed: None
Before starting this mission you might want to finish the quest called, Northward, in Ru'Lude Gardens to get a Map of Zvahl Castle. This quest is very easy to pick up and complete. This guide will be base on you having a Map of Zvahl Castle. Other requirements is that you should have a stack of silent oil and prism powder on you. To make trekking through the Castle much easier and faster for everyone.

Ok when you are ready, pick up this mission at the Gate Guard. Head over to Chateau D' Oraguille and talk to Halver. After that's done talk to Prince Trion in his chamber. You must talk to the Prince and get a cutscene from him asking you to head over to the Castle. If you fail to talk to the Prince then you will have problems entering the BCNM fight that is ahead to come. Now once all that is done, you'll need to get a party of level 58+ together to complete this. It's possible to complete this with a party of level 55+ but it's much better and easier with a party of 58+.

Once you teleport to Xarcabard head over to about D-7 and zone into Castle Zvahl. Now for the first part of treking through the Castle, most of the mobs will be checking as Easy Prey to a party of level 58+. Demons aggro to sight while Ahriman(Eyes) will aggro to both sight and sound. It's best to keep everyone sneak and invisible to make the trek faster and safer. From the first map of Castle Zvahl Bailey, F-9 and downstairs then head west until you zone into the second map of Castle Zvahl Bailey.
From the second map, go either left until you reach stairs. Climb up them and head to the bottom left corner on the other side. Once there go back down the stairs. Hugging the western wall run until you reach a path that cuts under the 2nd floor looking like a small bridge at H-9.
Once you run pass under the bridge go west a bit then head north along this new path. Go straight and you should see stairs, go up them. You should see a hallway just to your left or east of you. Run toward the halllway and zone into Castle Zvahl Keep.
From Castle Zvahl Keep zone of Castle Zvahl Bailely make your way toward H-7. Open the iron gate. From here it's a small maze that you need to make your way through. If you have a map and you should have one due to completing that quest mention earlier, you can zoom into your map and see how to make your way through the small maze of Iron Gates. Your goal is to make it to H-6 where it will take you to the second map of Castle Zvahl Keep.
From the second map of Castle Zvahl Keep, navigate your way toward E-8 where you will enter the third map of Castle Zvahl Keep. This should be simple enough to do, just follow the direction on the map.
From the third map, just go straight ahead until you see a teleporter. Hop on the teleporter and continue to take each teleporter until you reach the fourth map of Castle Zvahl Keep where there will be no more teleporters. In regards to the third map of taking the teleporters, keep invisible up and you should be fine. Don't worry if you miss the teleporter because it will re-appear again after every 30 seconds or so.
You should be on the fourth map after going through all the teleporters. Just make your way to the Iron Door at G-7 on the fourth map and open it. Zone inside to the Throne Room.

Once you are inside the Throne Room, just head straight until you arrive at the door of the Throne Room. At this point it's time to prepare for the fight with the Shadow Lord. Buff your party and get ready for some battle plan. The fight with the Shadow Lord will be a two parter as you need to defeat him in two separate forms. The first form of the Shadow Lord is pretty much immune to most magic attack. Shadow Lord will also use his 2 hour, Invincible, a few times once his HP is low on the first form.
Here's what you should do for the first form. Fight the Shadow Lord as if you were fighting any other type of mob. Only difference here is that Mages such as Black Mages and Red Mages should not nuke at all. This is to conserve MP for later usage. Melees should only use regular physical attack to knock down Shadow Lord HP. Save your TP and Weaponskill for the second form. Once Shadow Lord HP start getting low and he uses his 2 hour, Invincible ability, then this is when it's time for the Mages to go all out and nuke Shadow Lord. Repeat the process again if the Shadow Lord uses his 2 hour a second time. So in short only nuke when Shadow Lord uses his 2 hour and save TP and WS for second form.

Now once the first form is defeated, you'll get a cut scene. Once the cut scene is over prepare for the second form of Shadow Lord. This time around, Shadow Lord HP is lower and in general he's a lot easier to take down. Only difference is that Shadow Lord only attack with be an AOE attack that does damage to all party members. At this point, all the melees, tank, and mages should unload their magic and weaponskill to take the Shadow Lord down in seconds. If you use this strategy then you shouldn't have any problems at all with Shadow Lord, assuming if you are at the appropriate level.

With Shadow Lord defeated, report back to Prince on what had just transpire. You may also need to talk to Halver. You should recieve you all important Rank 6 upon doing so. Now as a Rank 6, you can begin the Zilart Missions and of course Dynamis as well if you are at the right level. As a side note as stated in the last cut scene in the Shadow Lord fight, head over to Norg once you finish talking to the Prince.