It is a hard dungeon so far. This means that you don't have to commit the same mistakes that many people do, which is about to go there uprepared. It is good to have knowledge about this dungeon and this is the purpose of this post.
Consumables: Are a must use for this dungeons, such as: charms, carving or savagery scrolls, noctenium infusion, Nostrum energy (for meele) or ranger (for casters and archer), HP and MP potions as also other like Bravery or Hero potions.
Massive flowers appear: Two flowers will spawn, which Vitalia Flower and Ardent Azuria. Vitalia Flower restores HP and Ardent Azuria increases power. It is better that a long range party member or the lowest DPS in the party handle those. If the party does not have any healer, then healing flower should be taken.
Boon: This is a free resurrection stage that will rise one or two fallen party members. When three Boons were activated, that means not more free resurrection. It is better to not die and keep the DPS as fast as hard as possible.
First Boss: Ardentmaw
It is Baboon from Balder's Temple, with the same attacks. It does a lot of jumping. Its jump attack is a strong medium range aoe so it is important to dodge it but not as fast as it jump, otherwise you will take damage and knock down by landing exactly when the boss lands over you. Avoid frontal attacks, so move around it in order to do back damage then it does an attack or dodge it through. Casters, archer and lancer can do offensive dodge in order to be safer and get the chance to do back damage. Casters should not be so close and either so away. It does an aoe in which throw rocks, during this stage some red circles will appear around the boos and you fastly should dodge out from those.
Announcements and mechanics:
Ardentmaw moves toward the sacrifice: Previously the boss will move to the middle of the room and the announcement will appear. Fastly you have to approach to a group of lambs, called Savage Lamb, and destroy them in order to knock down the boss and prevent it to get a buff. Otherwise, it will get a buff and then it will be jumping over and over, better to dodge it.
Ardentmaw moves toward the bananas: Previously the boss will move to the middle of the room and the announcement will appear. Fastly you have to approach to two banana trees and destroy them in order to knock down the boss and prevent it to get a buff. Otherwise, it will get a buff and then it will be jumping over and over, better to dodge it.
Ardentmaw moves toward the herbs: Previously the boss will move to the middle of the room and the announcement will appear. Fastly you have to approach to a group of plants (near the entrance), called Verveblossom, and destroy them in order to knock down the boss and prevent it to get a buff. Otherwise, it will get a buff and then it will be jumping over and over, better to dodge it.
Say hello to my little friends: The boss will dissapear for a while and a group of sloths, called Ardentmaw's Avatar, will spawn for three rounds. Three monkeys must be killed in each round, which are those with floating text saying "Squeek! Squeeeekk! . If you fail or kill other monkeys without floaring text, a wipe will be inminent. Even so, it seems that it is not so clear for some people so you must not AOE them and the sloths will be close with others when they spawn. You have to kill each sloth with floating text when those get away from the other sloths with not floating text.
What is this? Fresh meat?: Nimistrix's Avatar (Similar to Argon Corpus second boss) will spawn and lock on one party member. The party member being aimed, by the Avatar Bird, has to keep moving and dodge as fast as possible when the Bird's eyes blink in red and excecute Dive Bomb attack.
Silence: Read about Silence What is this? Fresh meat?
Second Boss: Forengula
It is similar to Sand Lizard nearby of Zulfikar Fortress and from the old Crucible of Flame dungeon. It does the same attacks like breathe attack, tail swings and AoE attacks.
Announcements and mechanics:
Rocks rise from the ground Take Cover!: Some big and tall rocks will spawn around. Party members have to hide behind these rocks but not so close to the rock because the boss can still kill a member by crashing against the rock. Mostly the party member with the secondary aggro ring, purple, has to hide behind the rock. The boss will run toward the member with the secondary aggro and if this one is behind a rock, the boss will crash against the rock and end up knocked down.
Forengula summons push pods: Some plants alike mobs will be summoned, these have a long range aoe attack that push you away. This could be benefitial sometimes and sometimes not. It is better to kill the pods around the area where the party will keep fighting the boss.
Stop playing with your food!: Nimistrix's Avatar will spawn again and will lock on one party member and excute the Dive Bomb attack. After the Dive, the Avatar will do another medium range aoe attack at the same spot where it fell. So, it is better to dodge it like before and then take some distance away from the spot where the bird fell down.
Too much: Read about Stop playing with your food!
Useless!: Read about Stop playing with your food!
Last Boss: Nimistrix
It is similar to the second boss in Argon Corpus dungeon and Val Tirkai's wold boss. It does the beak attack, wing attack and the Dive Bomb attack. Aid can be optain through crystals like those in Channelworks. There are 3 crystals, a sorcerer, a priest and a lancer. You can only obtain two NPC.
Announcements and mechanics:
Nimistrix absorbs nature's energy: The party members have stun the boss, otherwise it will get a power buff with 10 minutes duration and it stacks. Priest's sleep debuff works well to interrup this phase.
Nimistrix cries out!: The party must destroy the egg as soon as possible. If you do not destroy the egg, minions will appear and attack you as also party will receive a slow movement debuff.
Nimistrix's skin is empowered!: Healer will have to cleanse this buff because This defensive buff stacks. NPC Priest can do this job.
Nimistrix calls a storm!: A few circles will spawn around the boss, these are the safe area in which the party members must stand inside during this stage. This is a wipe mechanic that will kill any member outside of the safew circles, which have arrows poiting inside them.
Nimistrix dives IGN: The boss will lock on the party member that was named in the announcement and it will do a Dive Bomb attack to the locked on member. The party member has to dodge the attack as fast the the eyes blink in red.
Credits: Special thanks to Melethiel for making this guide.