From most clear guides for this fight, provoke tank lists somehow have been missing out the beloved slime so I wanted to do a clear featuring him.

Team composition

• 5* Enhanced Liquid Metal Slime: provoke tank
• 6* Summer Fina and Lid: water imbue, fire damage, Barfiraga (from 3* Carbuncle)
• 6* Sylvie: HP barrier, magic mitigation, MP heal
• 7* Aerith: HP barrier, reraise, cure charm (6* is okay as well since I did not end up using any of her CD during my clear)
• 7* Esther: damage dealer

Comment: Liquid Metal Slime with Metal Body 2 has 80% Magic and Physical resistance, 50% all elemental resistance and 30% physical evasion. With no extra gearing, he sits on 1400 DEF so physical ST from boss does almost to no damage to him. With Barfiraga from Carbuncle, LMS becomes completely immune to fire attack. The major issue for LMS is to survive the ST magic attack which is why general mitigation and magic mitigation become crucial for this team composition. With that in mind, Sylvie and Aerith are replaceable with other units that can give said mitigation and a form of re-raise.

Gearing

• 5* Enhanced Liquid Metal Slime: flat HP accessories (e.g. Sephiroth's Boots, Lucky Ingot, Crimson Wedge) and equipped with Golem
• 6* Summer Fina and Lid, 6* Sylvie, 7* Aerith: at least 30% Fire resist and some form of fire damage (from espers such as Ifrit, Phoenix or fire weapons); general support gear for survival and LB fill rate
• 7* Esther: at least 30% fire resist, demon/fairy killers and LB damage

Clear video

Here

Suggested rotation

• Enhanced LMS: first turn provokes using Golem. With LB crysts and self LB filling passive, LMS can use LB to provoke from turn 2 onward then guard until provoke wears off.
• Aerith: keep general mitigation and HP barrier up all time and keep re-raise on LMS are her main jobs. On free turns: do fire damage, using sealing skill or cure people are are charmed by Summar Fina and Lid's sexiness (or just use Charming Protection from Lakshmi - this wastes a turn tho)
• Summer Fina and Lid: water imbue two Esthers is the main job. On free turns - do fire damage or break water imperil via LB or use sealing skill
• Sylvie: keep magic mitigation and HP barrier up is the main job. On free turns: MP heal, fire damage, use sealing skill
• Esther: Spam LB > T-cast Bolting Strike > Spam LB to eternity (this is why I love Esther, such simplicity!)
  

Tip: the adds summoned by boss can be confused and paralyzed so if your Esthers fail to kill them on sight, use Toxic Rain or Chaos Grenade to halt for one more turn without getting wiped.