This fight has 4 phases, each of which is signified by it using Kathwack. The phases are 100%, 69%, 39% and 9%. The Mimic is a level 99 mob with boosted stats, so hate mechanics totally suck for this.
Kathwack: Darkness magic/breath damage that either KOs or removes RR similar to Odin MT. We saw this move do as much as 3K damage.
Luopans will always be KO'd, so it's a good idea to stagger BoG and EA.
Valiance drastically reduces Kathwack damage, making it much more manageable. The damage can also be absorbed by RUN, making us think Liement and All For One would also work on Kathwack.
Death spell: No matter what, it always casts Death every 30-40 seconds. Sometimes it'll do AM2 or aga, but the vast majority of the time it casts Death. While Martel had strangely high resist rates of Death on RUN, the only realistic way to reliably prevent it is Lullaby, as it's 100% immune to Stun/Silence. With best possible BRD macc set, food and Warlock roll, you can Lullaby it for up to 20min straight.
Death Trap: Hate Reset. This is almost certainly a retaliation move it uses when you don't meet a certain condition. For us, it used it after what seemed to be every 3rd WS during the 69-39% phase. With Attunement and Barthundra the stun duration is fairly short and you can power through it. Divine Caress Poisona will allow you to resist Poison 3-4 times.
Guilded Torpor: AoE sleep. This landing on BRD at the wrong time can be very bad. If used, Martel would Frenzy Sallet and use Healing Breeze as soon as possible which made this move a none factor.
Booby Prize: Picks and random debuff and applies it to everyone in range. Really not dangerous at all except for when it does Petrify, which always seemed to last for 2min even with mages in max meva gear. Should have someone very far back that's /whm to Stona just in case this goes off.
Pandora's Curse: Darkness based magic damage that has a strong bio and does 30~ seconds of all stats down. Can only use starting after 39%.
Pandora's Gift: Box just randomly heals you. Might be a reward mechanic for doing something correct. Only saw it under 39%.
Other physical based chest TP moves: Double Wammy/Slam/Calamitous Collapse. All are pretty weak and not a factor.
100-69% Phase 1:
•We had the RUN run in solo to open every chest until the mimic spawned so they were the only one to eat the first Kathwack. After it's popped the BRD sleeps and we applied full buffs.
•No special mechanics. Takes lots of damage from Physical/Magic and no absorbs.
69-39% Phase2:
•In the video, we start directly into Phase 2. I had already gotten it down to 69%, but accidentally healed it back to 95%. True Phase 2 in the video starts at 69% HP.
•Phase 2 mechanic to do damage is alternating skillchains. Either light or dark based magic will heal or damage it, you can test which by casting fire. If fire is absorbed it, darkness will deal damage, if fire damages it then light will damage it. Skillchain damage is vastly amplified during this stage for both damage and heals.
•Death Trap spam begins. Usually I can get off 1 clean SC and use the opening weaponskill for the following SC, but then it retaliates with a Death Trap.
39-9% Phase 3:
•Pandora's Curse unlocks which can be dangerous.
•Gains massive DT, but we found that making sure it was in fire absorb mode before starting a 3 step skillchain, the 2nd SC would do considerable damage. With this we were able to whittle it down to 9%.
Example: Tachi: Shoha > Tachi: Kasha will make light which will heal it but not for a ton because Kasha is pretty weak, usually around 5-10K damage. Fudo after Kasha will make Level 2 Light or Radiance, which does 20-30K damage.
9-0% Phase 4:
•Will use Might Strikes and gain a MASSIVE Plague and Bio aura. I'm not positive but it felt like plague was removing 500~700 TP per tick.
•It felt like all mechanics were gone again. No absorbs or DT. I feel like the goal is just to "beat the aura" type thing. ***can go very, very wrong if the WHM gets stunned from Death Trap while poison+bio are ticking away.
•We layered RUN SP> WHM SP2 + SAM SP2 to prevent Death Trap's stun from ever landing.
Final Notes:
•Possibly part of its retaliation mechanic, it will sometimes get a Muddle and Avoidance Aura. This can interfere with using RR items so make sure it's down when trying to use.
•Once it's dead, the Gold Chest in the center reappears and you can click it to get your rewards.
•If cleaned up more and no mistakes, I can see this being cleanable in 15 minutes or so.
•SAM solo DD isn't 100% needed. Any other DD + COR can easily mimic what SAM was doing with SC, but we're already set up very well to take advantage of multi-step SAM.
•We used Mars Orb for this run. Will prob do Venus for next/from now on.