Dimensions End: Entropy - Tier 13. This tier has the enemies Resistant to Melee Damage. The enemies have high SPD, Attacks with High Turn Rates, AoE Attacks and Generic Status Down Immunity. The recommended roles would be a Healers, Battery, Damage Dealers & BRV Shaving. The bosses' total HP is 8,800,000. The turn requirement is 110. The DPT you need is 76K.
Wave 1 (Boss Wave)
Elvoret & Spark Eye. Both of these bosses get more dangerous the longer they are alive. The Elvoret's stackable framed buff (Tower's Dark Wings) increases its own HP damage dealt, Debuff Evasion and ATK, while it lowers your DEF, iBRV and mBRV. The Spark Eye increases it's ATK every time it does Capacitance, and on the third cast it also increases its DEF.
The best strategy is to take out the Spark Eye first, as the familiar Supercell (BRV Gain + AoE BRV + HP (split) attack) is extremely devastating and can wipe your party. Keep the BRV of the Elvoret in check and all should be fine.
Debuffs Inflicted: DEF/iBRV/mBRV Down
Wave 2 (Boss Wave)
Two Jeweled Turtle (Fire Resistant). They gain massive BRV when they go in hiding so BRV shave it at all costs or you will likely die. Their only AoE attack is a BRV+HP Attack, so brace yourself for this. Upon using Jewel Bullet, they buff mBRV up, cleanse unframed debuffs, and also have high turn rate if breaking or attacking a broken target. Be careful or this will kill your run.
Debuffs Inflicted: Delay, Sap
Wave 3 (Final Boss Wave)
Marilith Gloria (left) & Marilith Tempest (right). Kill the Marilith Tempest (right) first, as it enrages while the Marilith Gloria (left) does not.
These two have a lot of AoE attacks. The Maralith Gloria buffs itself, inflicts HP Poison, and has high turn rate when breaking or attacking broken targets. The Marilith Tempest meanwhile is a BRV+HP machine. Thankfully these two have deceptively low HP, so balance bursting them down while also making sure you have enough heals left to stay healthy in this last wave.
Debuffs Inflicted: Physical Resist Down, Thunder Resist Down, iBRV/Def Down
Eald'narche & Arciela provide your team with protection from the frequent HP attacks in the quest. Their utility to faux-paralyze enemies gives your team breathing room and comfort.
Garnet & Fujin can enchant & imperil your allies to increase damage and also bypass melee resistance.
Aerith, Alphinaud, Arciela, & Garnet all provide powerful auras and healing while the former two mentioned also have good damage per turn.
Keiss, Trey, Cloud of Darkness, & Aranea are all extremely strong damage dealers that end the fight quickly, which is important as the damage per turn to complete has increased by 16k vs Tier 11 & 12. Cloud of Darkness & Aranea also provide delay while Keiss & Trey deal large damage outside of their normal turns. Keiss & Fujin frequently launch enemies to help amplify damage for the team.