The Secrets of Worship

Prep Tips!

 * Make sure everyone in your party has at least looked at this page on the Wiki so they understand what is going on. Give them the wiki address in game: wiki.ffxiclopedia.org, and just have them search Promathia Mission 4-3; spelling is important. It's ok to be a little bit assertive when setting this up, as failure means people lose a lot of time; Sacrarium is often a very time consuming investment.
 * Get a Coral Crest Key. Many people wait until the mission to get this key, however this can often create a lot of problems. One thing that you need to understand is that only 1 member is going to get the Sealion Crest Key, so if that member leaves due to time constraint or party wipes, then you have to kill Keremet again with another party to get another Sealion Crest Key. You having a Coral Crest Key will speed things up a huge amount, and you really will be the hero of the day.
 * One idea to accomplish this is by shouting in town for people to come to Sacrarium for the purpose of Subligar farming, and then Cast Lots on a Coral Crest Key when it drops. This is beneficial because you wont have to worry about Fomor Hate rising again from having to kill to get a Coral Crest Key after you spent the time lowering your Fomor hate.
 * Lower your Fomor Hate. This is so important as the Sacrarium mission takes a very long time, and your ability to walk through the Fomor without agro, especially for the final NM fight, will help a lot. You can count this as almost a required step. The combination of having a Coral Crest Key, and lowest Fomor hate when you do this mission can knock 1-2 hours off the overall time to complete the mission.
 * Note that an additional benefit of taking the time to do this is that there are many quest items dropped off the Lufaise Meadows/Misareaux Coast beastmen which will end up paying you for the time you spent lowering your Fomor hate.
 * Bring Silent Oil(1-2). Nothing in here requires the use of invisible, and there are only a few times where you will even need Sneak. But for the times you do, it will speed up the process if you can sneak yourself instead of waiting for the Healer to sneak you. The worst thing you can do is be the one who is hanging behind because your sneak wore off, or end up dieing or getting other members killed because you agro'd a mob. 1-2 Silent Oil is cheap enough for anyone's pocket to afford.
 * Bring Poison Potion(3-4) for your fight with Old Professor Mariselle. He will use Sleepga very often, and your ability to keep damaging him instead of being slept while he attacks and then eventually teleports elsewhere in the room, will greatly increase your chances of success.
 * Bring Hi-Potion(5), Regen-drinks and Refresh-drinks. The Old Professor Mariselle fight, and its location, pose a tricky situation, and having these consumable items will greatly increase your odds of success. The Regen-drinks are also good because it would effectively counter-act the Poison Potion effect. Pear au Lait(1-2) works well for this, but even something as simple as Selbina Milk(12) will be good if you keep using it when it wears off, as it will offer you HP restore when there is the short break in the fight when he teleports around the room.

Walkthrough

 * Speak with Justinius at (J-6) in third floor.
 * Click on the Walnut Door at (K-7) upstairs next to Parelbriaux for a cutscene.
 * Head to the Iron Gate in the northern part of Misareaux Coast (G-4) for a cutscene. After checking this, you now have access to Sacrarium
 * This is the entrance to the Sacrarium. This area is capped at level 50. Note that the entrance maze walls on Map 1 will shift with each Vana'diel day.
 * Traverse the Sacrarium maze until you find the Fomor. Kill the Fomor until you get two Rare/Ex Coral Crest Keys. You can do this mission with only one Coral Crest Key, but it will be necessary to have an extra person to stay behind to operate the door, which means they will not be able to assist with the NM fight.

Keremet

 * First, kill the skeletons in the two hallways (J7-8) and (J8-9). The two hallways, are each lined with 6 Skeletons. The Skeletons don't aggro or link, and are weak, but if anyone attacks Keremet they will rush to aid him. Defeat all 12 Skeletons first, then pass through one of the doors at the end of the hall (K-8). Once they are defeated you have about 30 minutes before they respawn.
 * Now you can kill Keremet, a Corse NM. Keremet is at the far side of the room. Wait for the taurus to wander to one side and then pull Keremet back through one of the doors into one of the hallways where the Skeletons were. Only one person should pull Keremet while the others wait in the hallway. This is a hard fight that should be taken seriously, but does not warrant the use of 2 hour skills.
 * Keremet can be Silenced. He is highly resistant to stun, sleep, and Blizzard spells.
 * Like all Corse, Keremet can Charm (Status Effect) members of your party with the Danse Macabre TP attack. Charmed party members MUST be slept. He has ice spikes which can be dispelled and an AoE silence move.
 * A Beastmaster makes this fight much easier; a Blubber Eyes under Familiar does a lot of damage and pets are immune to Keremet's Charm. Two Blubber Eyes can duo Keremet.


 * Kill Keremet and obtain the Sealion Crest Key (EX). Give it to someone who doesn’t have either of the Coral Crest Keys.

Old Professor Mariselle

 * Optional step, but recommended - This is a very good piece of advice, that anyone reading the Walkthru should pay attention to. The final NM(Old Professor Mariselle) you fight will be inside a room full of Fomor. Unless you get the lucky chance of Old Professor Mariselle following you out to the hallway each time where you can do a 20-30 second amount of damage before he teleports back into the room, then you would have to kill all the Fomor in the room first, which can be very hard to maintain given respawn times. The problem with this recommendation is that some player may have really high Fomor hate and the option of killing enough Beastmen to lower it may be more time investment than the party is able to give.
 * The recomendation: Head back to Misareaux Coast and kill Orcs and Gigas to lower your Fomor Hate. Check with Resauchamet at (J/K-6) of the upper floor of Tavnazian Safehold. Lower your Fomor Hate to level 1, where Resauchamet will tell you that you have a “good head start.” (If you have max hate, about 50 kills will lower it to level 1.)


 * Head to (H-7) in the Sacrarium and find a door at (H-7) with two keyholes: one SMALL and one LARGE. The first party member will trade the Coral Crest Key to the SMALL HOLE; you will hear a click. The other party member will trade the Sealion Crest Key to the LARGE hole; the door will then open, and the Coral Crest Key holder will be immobilized for a moment.
 * You have a limited amount of time to trade the Sealion Crest Key after the Coral Crest Key has been traded, so make sure the key holders are both ready. (Both locks cannot be opened by a single person!) You will keep your Sealion Crest Key, but your Coral Crest Key will break. If the Sealion Crest Key isn't traded quickly enough, you will lose your opportunity to get the door open, and you will have to get another Coral Crest Key.


 * Find and click on the Wooden Gate at (G-8) for a cutscene, and then head back out the locked door. If you do not have another Coral Crest Key, you can leave a member behind to open the door with the switch, however they will not be able to obtain a reliquary key.
 * There are six classrooms, three on the north side of the area of Sacrarium you are in and three on the south side. Each has a ??? on a desk in each room. Check each ??? until you spawn the Ghost NM Old Professor Mariselle.
 * He summons two Mariselle's Pupils soon after being spawned.
 * Old Professor Mariselle casts Sleepga II and Silence, and uses Ghost abilities. He seems to have a fair bit of regen, so continuing to keep damage on is important.
 * It's highly recommended to use Poison Potions to protect against his Sleepga spam.
 * They will teleport around the room a couple of time during the fight (every ~20-30 seconds). Mariselle will "despawn" first, along with his two pupils, and then respawn randomly somewhere in the room (the pupils also spawn randomly, sometimes all three are far apart after a teleport). Even if pulled outside the room, it will respawn somewhere in the room again, so this way of avoiding Fomor aggro is not recommended, but will work if you have sufficient Refresh and Curing magic.
 * If one of your party hasn't reset Fomor hate, you will have to clear the room first, as pulling Old Professor Mariselle out of the room does work, but can take a considerably long amount of time, and you will take extra damage as he casts on you from inside the room before coming forward.
 * It's possible to have a summoned avatar, beastmaster pet, or automaton to draw him out after teleporting, as they will still have hate on him.
 * If everyone has reset their fomor hate, don’t use AoE abilities to avoid unwanted aggro.
 * The Mariselle's Pupils are weak. However, if you kill them, Old Professor Mariselle will summon more. They CANNOT be slept.
 * DO NOT use Tractor, if you do then you will have to get the ??? and kill this NM again.


 * Kill Old Professor Mariselle and check the ??? again for the Reliquiarium Key. Any ??? on any of the desks in the rooms will allow you to obtain the Reliquiarium Key.
 * Proceed back to the locked door and open it with your second Coral Crest Key and the Sealion Crest Key, using the same method as before. Alternatively, simply have someone operate the switch on the other side.
 * Head back to the Wooden Gate and click it again to end the mission.
 * Once the cutscene is over, you will end up on the other side of the Wooden Gate, unable to open it from that side.

Game Description

 * Mission Orders: Now that you have learned the Wyrmking's plan, you must travel to the fourth mothercrystal. Nag'molada has informed you where the stone lies. However, you will need the amulet you lent to Prishe before you are to make your way there.

Game Script and cutscene video
COP 4-3 Video hosted on Filefront.