Dimensions End: Entropy - Tier 9. This tier No Resistances. There are multiple bosses on each wave. They have strong AoE BRV Attacks, multiple element resist/absorb, high defenses and immune to generic defense down debuff. Recommended roles are high DPT, Tank, HP Healing, BRV & HP Reduction/Nullify. The bosses' total HP is 5,800,000. The turn requirement is 90. The DPT you need is 60K.
Wave 1 (Boss Wave)
Two Death Riders (Dark Absorb) and One Berserker Armor. These bosses spam a lot of AoE BRV Attacks and will routinely need to be shaved. AoE BRV shavers will flourish here. You will likely get broken often and this can lead to your death if you're not careful. Try to take down the Berserker Armor first as the Death Riders are less threatening.
Wave 2 (Boss Wave)
Ice Gigas (Fire Weak, Ice Absorb) and Iron Worm (Fire Weak, Thunder Weak, Ice Resist, Dark Absorb). Worm does gravity based HP so sustained heals are good to prevent getting caught off guard. Ice Gigas are potentially dangerous when they break you. It is recommended to take out the Ice Gigas first as the Iron Worm's HP damage is consistent thus easy to manage.
Enemy Debuffs: IBRV/SPD Down
Wave 3 (Final Boss Wave)
Plant Golem (Wind Weak, Earth Null) and Phantom Mail. This wave likes to mess with your turns. Phantom Mail hides itself in your turn order, making it difficult to know when he will attack. Meanwhile the Plant Golem delays you. It is recommended to prioritize killing the Phantom Mail. You can summon as well to burst it down. Just be careful on using Brothers Summon as the Plant Golem won’t receive any damage from Earth element.
Enemy Debuffs: SPD/Turn Rate Down
Most Used Units. Vayne is the most used unit for this tier. His excellent DPT, free turns and break mechanics allow you to manipulate turn order efficiently. He's followed by Paladin Cecil who has high DPT when his imperil is inflicted. Rosa with her auras, AoE DPT and healing. Galuf with his mechanics to block, evade and counter incoming attacks. Papalymo with his high DPT. Edge with his party evasion. Noctis and Yuri with their high DPT. Beatrix with her buffs, HP DMG Nullify and DPT. Penelo with her great overall support.
EX Only Units. Sherlotta and Lenna work well as usualy. Layle with his rework allow him to be useable with his base EX.
Summons Used. Ifrit is popular to boost your ATK though Shiva and Brothers are not far boosting your ATK/SPD and MBRV respectively.
Top Unit. Vayne with his EX+ weapon gives your excellent DPT and efficient turn order manipulation. Pair him with support characters such as Paladin Cecil, Rosa, Beatrix or Penelo. Tanks work well too like Galuf and Edge. Alternative high DPT are Aranea and Papalymo.