I decided not to post anything until I really clear everything and have tried my way to optimize everything (So I can... actually have something to write about)

The first boss, is trivial. So the interesting part is always be the 2nd boss. Lots of RNG playing. But there's a recurring theme in area 1-4

• Area 1: if Kokuryu focuses on water, give up. Because my party is not designed to withstand the 75% water imperil
• Area 2: if Phoenix focuses on fire, give up. Because my party is not designed to withstand the 75% fire imperil
• Area 3: if Anima focuses on ice, give up. Because my party is not desigend to withstand the 75% ice imperil
• Area 4: is actually a bit different, since it will imperil you by 60% anyway on T1. So I had to concede a bit on MAG gearing for light/lightning resistance. The exit call will be made if either Rem or Ace is paralyzed on T3.

Dark Kokuryu

I felt this is the hardest bosses from the first 4 area to hit the damage cap and perfect score. First I realized BB Rem alone isn't enough to get damage cap score. So I wasted all the ticket and voila, got my Ace. Then I follow suit to Omniprism Elly. Unfortunately, they still haven't hit the damage cap (probably around 1.9b or low 2b). Once I figure out how to hit max chain when swapping Sylvie for Locke, damage cap is reached. IIRC, It was 9 (Water Dragon) 12 (Gelid Spear) 81 (Triple BS MMXon, Rem, Ace) 1 (Elly), netting me 102 chain.

Dark Phoenix

I didn't notice how low my damage was until I realized there's damage reduction on Phoenix. So I had to keep in mind that Black Mirror should be done on T2. At first, I used Ang for bird killer, but assessing how he's literally useless other than "very low" bird killer. I just decided to go with Malphasie who provide similar killer, but can provide AR chain. That way, I can fit more DD that ALSO provide Fire/Wind resist on T1: MI Lasswell. There's a bit RNG going on until I hit damage cap. It was all good.

Dark Anima

This is the 2nd most difficult optimization for me. I was hung up to the idea of "there's no way WH Raegen, Kadaj, AC Cloud, and Cid hit the damage cap". Thanks to unit search, I found out Epsilon Nichol is perfect for this: (1)He provides the needed anti-stop (2) He gives huge LB fill on T2, so Raegen can unleash LB on T2 (mod boost and 120% fire imperil) (3) He gives the needed Dark and Ice resistance (100%) (4) HE CAN DO FREAKING AR CHAIN. With all those known, then reaching max chain and max damage was trivial.

Dark Alexander

The easiest boss among 4. As soon as I realized Locke can do very potent LB on T3, damage cap and max chain was reached easily

Dark Bahamut 1

OK, I admit. Before I saw togeo's AI breakdown, I went with Cecil. But once I identified which element need to be taken care of and what can be written off, I deduced these last 2 bosses are just another tankless battle. The dispel happening on T3 is another signal that you shouldn't pend the burst longer than T3.

• MI Lasswell again, easily fulfilled the condition of "Every unit must have 100% fire and wind resist"
• Cid's Sky Dragon Squall is just right for providing the needed mirage on the first 2 turns.
• "MMXon need to have 100% dark resist" was the next thing I realized
• Then Esper/Gear optimization: Ifrit gives anti-blind which MI Lasswell lacking, AC Cloud had to forego Erdwin's Coronet for Genji Helm anti-paralyze, and Beatrix need to get her Eyepatch for the anti blind
• Strategy optimization would be: Lasswell cannot touch the boss until T3 because he wield that free ice katana from the 1st DV event. Hitting with 2 element is a bad idea. Consequently this hurt his damage on T3 since he can't get the mod boost from Fatal Bloom

Dark Bahamut 2

Like the first one, but with some caveat that:

• Beatrix no longer there to add the 16 extra hit to hit chain cap
• The highest burst I can do with Cid Cloud was 70% HP on 70% break. While his HP on T2 is still at around 94% at best

So I decided to drop Cloud for Gilgamesh. With this, he can shave some HP along with Lasswell on T2. Both of them alows Raegen LB act as a "finisher", shaving down the HP down to 77%, and makes the T3 nuking is actually doable. Chain cap reached (4x triple AMoE 2 hit Cid land Locke's normal attack), no damage taken, it's all well.

Closing

I think I could do better on 5-1 and 5-2 if I have Akstar or SD Akstar Katana. sigh... What do you expect from free katana. There's Virtue Drake Lance that I could try, but I doubt it'll improve the score by much.

Getting Raegen's LB ready on T2 was painful. But it was well worth the damage (and imperil, in case of Anima)

Getting MMXon is a blessing, so does getting Ace and Rem. MI Lasswell is a blessing in a disguise. Gilgamesh finally have the spotlight with better-than-expected performance (hello 150% innate dragon killer)

I can't imagine how far I would fall behind if I didn't have those aforementioned units. Maybe rank 3k this time around?