Last of the Red Wings - Ultimate ++ CM
Edge - Eblan Doppelganger (
USB SSB - Hastega + Last Stand + Phys Blink)
Edward - N/A
Golbez - N/A
Rosa - N/A
Porom - Sync (SSB - Hastega + Curaga)
I originally tried this with a melee party of Cecil, Ceodore and Golbez but without wall and any extra stacks of mitigation, Baigan does way too much damage for one healer without a BSB.
You're dealing with a crapton of AoE here of both types as well as AoE Silence and Blind as well as the boss casting Hastega on itself. Dealing with these status effects is far more important than trying to reduce the AoE Fira through Fire Resist accessories. Even with my party all backrow, unless you're running Wall, Baigan is still going to do a crapton of damage to you.
Opted towards the "turtle and pour everything into one DPS" strat, namely Golbez with Memento Mori and Serah's Moonfrost Arrows CMD2 spam. I wanted Mastery so I went with Serah's BSB, but if you just want to CM clear, Edea's BSB would probably be better to burn him ASAP (as long as you have 3 characters alive at the end to deal with the arms exploding).
Last of the Red Wings - Apoc +
Tyro - Sentinel's Grimoire
Raines - Metamorphosis
OK - Vessel of Fate
Ashe - Dusk's Decree
Vanille - Transcendent Dream
My standard Mage Meta, literally rotating the 4th DPS to whatever the boss is weak against (which in this case Levi is slightly weak to Lightning). Older players should have 3 water resist accessories to make Levi hit like a baby, but this is longer than standard battle (as it should be seeing it's Apoc +). Asura is an absolute pain in the ass with her Dispel, but luckily it's only ST.