Kill time - 53 minutes~
Party Comp:
RNG/drg(ML50), RNG/drg(ML45), BRD/sch(ML50), COR/drg(ML50), GEO/rdm(ML28), PLD/blu(ML44)
Important notes to keep in mind
It is to be believed this encounter got a ninja nerf around February 2026. The exact nerf is unknown except Evasion. This evasion nerf was substantial - Roughly -90~ Evasion reduction from prior attempts.
It took a 50/50 coin flip 4 times in a row, toss up between Invincible or Elemental Sforzo from Bahamut. We needed 0 Invincible usage or we warped out.
On our clear we had 4 Elemental Sforzo in a row + Wild card reset which also reset the wildcard. A ton of luck.
We do not know if there is an "intended" mechanic or not, we could not find it. It's possible the strategy is to Alternate Physical/Magical damage on Bahamut depending on SPs, but his Magic evasion is FAR too high. We were getting resists on ML 50 BLM(stage 5 Prime) magic bursting with Crooked Warlock's roll, Bolster Languor/Focus, Rayke, storm 2 + SV threnody and Stymie saboteur Frazzle 3. Who knows if it's tuned correctly or not. We do not know if there is a way to remove the additional effects from the SPs outside of having them switch their SP at their next HP thresholds, if it's possible.
Mechanics we do know:
Chaos SPs 4-5 times in 1 health bar either Manafont or Chainspell
Bahamut SPs 4-5 in 1 health bar either Elemental Sforzo or Invincible.
Geomancy nerfed -50%
Main TP moves and spells that cause problems:
Absolute Terror - AoE Terror little under max healing range 15s
Horrible Roar - AoE 4 buff dispel over max healing range
Dispelga - Bahamut
Oppressive Yawp - Full dispel hits anyone over max healing distance centred around target which also removes all debuffs cast on Chaos.
Pellucid Surge - Non-Elemental AoE damage (maybe non-elemental) similar range to Oppressive Yawp centred around target (This will hit the bard regardless of where they are positioned since they are the main healer.)
Chaos
Takes -75% from all non-prime weapons
Manafont - gives Chaos access to Meteor for an unknown duration (varied from SP worth to the whole fight)
Chainspell - gives Chaos access to -Ga Enfeebling spells for unknown duration similar to Manafont.
Below 75% gains access to Tenebrous Surge + Luminous Surge
Below 50% gain access to Pellucid Surge
Must be killed close together with Bahamut at 1% - if you try killing Chaos before Bahamut is at the required % Chaos takes 0 damage and will Benediction.
Bahamut
No damage penalty except Light,Fire and Darkness. It is to be believed 5% dark resistance rank, 10% light and 10% fire. Rendered Those elemental damages useless.
Immune to Frazzle - requires Stymie.
Elemental Sforzo - reduces ALL magic damage by roughly -66% to -75% once Sforzo effect wears off. This effect persists until the next SP is used.
Invincible - reduces ALL physical damage by roughly -66% to -75% until the next SP is used.
Below 75% gains access to Gigaflare
Below 50% gains access to Teraflare
Strategy
Not much to this outside of usual ranger pew pew, with how much luck is needed the dps check is not horrible post-nerf. The hardest part is getting no Invincible usages. We'd warp out if Invicible was used and reset.
Zerg Bahamut first - we took him to 1% or as close as possible before he takes 0 damage. Once we think Bahamut is as close to 1% as possible we swapped to Chaos and zerged him from 100% to dead. The scary moment was both of them took 0 damage at the end, but luckily it went away then Bahamut fell to the ground. The exact condition to prevent the Benediction is unknown except what we prayed was the mechanic and it worked. Bahamut took 25 minutes from entry to take to 1%~ and Chaos took 28 minutes~ Chaos is much squishier than Bahamut which was why we opted to unload all Soul voices + Bolster on Bahamut early.
The biggest thing is positioning, we had to be positioned in such a way to limit how many AoEs the Bard is getting hit by.
Tank pulls Bahamut and runs into the West side of the room, left side of the stairs (from entry) then let both mobs come close then slow walk around the pillar to be tucked into the staircase with the back to right side of the staircase (from entrance).
Bard will position close to the North pillar, but within healing range of the Tank (at max distance of healing distance).
Rangers, Geomancer and Corsair stand ABOVE max shooting distance from the tank. Chaos' Oppressive Yawp is a full dispel + full self cleanse of all debuffs with a range of over max healing range centered on the tank. So that group has to be positioned within range of Chaos/Bahamut, but far enough away from the tank. The position we used was a tiny bit to the right from where we entered, nailing the position took a few trial and errors.
Geomancer needs to be able to cure the Bard. The Geo is healing the Brd and the Brd is healing the tank in a link formation. Geo is keeping Haste, Refresh and Cures on the Brd. Flurry on the Rng/Cor. Spamming Dia on Chaos when we fought him, Dia on Bahamut with the occasional slow/paralyze attempts.
I used /blu with Frightful Roar with the occasional Tropical Crepe before it got dispelled with Burst Affinity to attempt to Magic burst Frightful Roar to land. Landed for 6 minutes out of 25 minutes for Bahamut, minor improvements, but felt like floored land rate without food/Macc set/MB.
Buffs used:
Bard songs: Honor March, Minuet 5, Minuet 4, Prelude x2
Cor rolls: Crooked Chaos + Samurai roll
Geomancy bubbles: With SV songs - Geo Frailty, Indi fury, entrust STR | Without SV songs - Geo Fury, Indi precision, entrust STR
We did Soul voice extensions the whole fight. First Wild card came right when BRD comes to re-sing SV songs with nitro for the 1st time. If no WC reset we'd Cutting cards the BRD asap. Bolster just before the Wild card.
Some final notes
Firstly, I don't think this fight can be beaten outside of absurd luck mechanics, the amount of luck this required makes Bumba look like good design. Horrific luck needed - main reason this fight took so long to clear.
Secondly, either tank can work for this encounter. I went PLD to test stuff with Shield bash (It helped on Bahamut dps check briefly with dispelling Shell/Protect/Phalanx - very high Macc/DT set) and it just so happened to be the winning pull. Both tanks have their pros and cons with either mob.
Primes used for the fight:
3 Stage 5 Prime Earp
1 Stage 5 Prime Horn
1 Stage 5 Prime Shield
Thanks to all the folk who helped fill in to test random stuff while we were down members due to IRL <3
