Entropy 13

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. 

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

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.